* [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
@ 2024-12-07 17:14 syzbot
2024-12-09 6:25 ` Qi Zheng
` (2 more replies)
0 siblings, 3 replies; 14+ messages in thread
From: syzbot @ 2024-12-07 17:14 UTC (permalink / raw)
To: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86, zhengqi.arch
Hello,
syzbot found the following issue on:
HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
The issue was bisected to:
commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
Author: Qi Zheng <zhengqi.arch@bytedance.com>
Date: Wed Dec 4 11:09:51 2024 +0000
x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
__lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
userfaultfd_move fs/userfaultfd.c:1899 [inline]
userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed8de85af9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
</TASK>
Allocated by task 6070:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
ptlock_alloc+0x20/0x70 mm/memory.c:7026
ptlock_init include/linux/mm.h:2971 [inline]
pagetable_pte_ctor include/linux/mm.h:2998 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
__do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
create_huge_pmd mm/memory.c:5737 [inline]
__handle_mm_fault mm/memory.c:5986 [inline]
handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
Freed by task 6071:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2338 [inline]
slab_free mm/slub.c:4598 [inline]
kmem_cache_free+0x195/0x410 mm/slub.c:4700
pagetable_pte_dtor include/linux/mm.h:3009 [inline]
___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
__pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
free_pte+0x142/0x190 mm/pt_reclaim.c:31
zap_pte_range mm/memory.c:1780 [inline]
zap_pmd_range mm/memory.c:1822 [inline]
zap_pud_range mm/memory.c:1851 [inline]
zap_p4d_range mm/memory.c:1872 [inline]
unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
zap_page_range_single+0x45c/0x630 mm/memory.c:2018
madvise_dontneed_single_vma mm/madvise.c:859 [inline]
madvise_dontneed_free mm/madvise.c:940 [inline]
madvise_vma_behavior mm/madvise.c:1270 [inline]
madvise_walk_vmas mm/madvise.c:1502 [inline]
do_madvise+0x2774/0x4d90 mm/madvise.c:1689
__do_sys_madvise mm/madvise.c:1705 [inline]
__se_sys_madvise mm/madvise.c:1703 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888034718960
which belongs to the cache page->ptl of size 64
The buggy address is located 24 bytes inside of
freed 64-byte region [ffff888034718960, ffff8880347189a0)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34718
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823, tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
prep_new_page mm/page_alloc.c:1557 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
__alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
alloc_slab_page mm/slub.c:2408 [inline]
allocate_slab+0x8f/0x3a0 mm/slub.c:2574
new_slab mm/slub.c:2627 [inline]
___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
__slab_alloc+0x58/0xa0 mm/slub.c:3905
__slab_alloc_node mm/slub.c:3980 [inline]
slab_alloc_node mm/slub.c:4141 [inline]
kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
ptlock_alloc mm/memory.c:7026 [inline]
ptlock_init include/linux/mm.h:2971 [inline]
pmd_ptlock_init include/linux/mm.h:3078 [inline]
pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
__pmd_alloc+0x10b/0x670 mm/memory.c:6436
pmd_alloc include/linux/mm.h:2862 [inline]
copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
copy_pud_range mm/memory.c:1298 [inline]
copy_p4d_range mm/memory.c:1322 [inline]
copy_page_range+0x99f/0xe90 mm/memory.c:1420
dup_mmap kernel/fork.c:751 [inline]
dup_mm kernel/fork.c:1693 [inline]
copy_mm+0x12d2/0x2060 kernel/fork.c:1742
copy_process+0x1845/0x3d80 kernel/fork.c:2393
kernel_clone+0x226/0x8e0 kernel/fork.c:2805
__do_sys_clone kernel/fork.c:2948 [inline]
__se_sys_clone kernel/fork.c:2932 [inline]
__x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
page last free pid 6052 tgid 6051 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
__folio_put+0x2b3/0x360 mm/swap.c:112
__tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
__tlb_remove_table_free mm/mmu_gather.c:227 [inline]
tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
rcu_do_batch kernel/rcu/tree.c:2567 [inline]
rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
__do_softirq kernel/softirq.c:595 [inline]
invoke_softirq kernel/softirq.c:435 [inline]
__irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
Memory state around the buggy address:
ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
^
ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
==================================================================
---
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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If you want to overwrite report's subsystems, reply with:
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-07 17:14 [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte syzbot
@ 2024-12-09 6:25 ` Qi Zheng
2024-12-09 6:48 ` Qi Zheng
2024-12-09 7:00 ` Qi Zheng
2024-12-09 7:33 ` Qi Zheng
2024-12-09 9:31 ` Qi Zheng
2 siblings, 2 replies; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 6:25 UTC (permalink / raw)
To: syzbot, David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song
Cc: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/8 01:14, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
> dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
>
> The issue was bisected to:
>
> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
> Author: Qi Zheng <zhengqi.arch@bytedance.com>
> Date: Wed Dec 4 11:09:51 2024 +0000
>
> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
>
> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0x169/0x550 mm/kasan/report.c:489
> kasan_report+0x143/0x180 mm/kasan/report.c:602
> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
> spin_lock include/linux/spinlock.h:351 [inline]
> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
> userfaultfd_move fs/userfaultfd.c:1899 [inline]
> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:906 [inline]
> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fed8de85af9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
> </TASK>
>
> Allocated by task 6070:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> unpoison_slab_object mm/kasan/common.c:319 [inline]
> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> slab_post_alloc_hook mm/slub.c:4104 [inline]
> slab_alloc_node mm/slub.c:4153 [inline]
> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
> ptlock_alloc+0x20/0x70 mm/memory.c:7026
> ptlock_init include/linux/mm.h:2971 [inline]
> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
> create_huge_pmd mm/memory.c:5737 [inline]
> __handle_mm_fault mm/memory.c:5986 [inline]
> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
>
> Freed by task 6071:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2338 [inline]
> slab_free mm/slub.c:4598 [inline]
> kmem_cache_free+0x195/0x410 mm/slub.c:4700
> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
OK, so the problem is that ptdesc->ptl is not freed via RCU:
___pte_free_tlb
--> pagetable_pte_dtor
--> ptlock_free
--> kmem_cache_free (free immediately!)
paravirt_tlb_remove_table
--> free PTE page via RCU
In retract_page_tables(), it calls pte_free_defer() to free
ptdesc->ptl and PTE page via RCU, so there is no problem.
To fix it, will also free ptdesc->ptl in ptlock_free() via RCU.
> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
> free_pte+0x142/0x190 mm/pt_reclaim.c:31
> zap_pte_range mm/memory.c:1780 [inline]
> zap_pmd_range mm/memory.c:1822 [inline]
> zap_pud_range mm/memory.c:1851 [inline]
> zap_p4d_range mm/memory.c:1872 [inline]
> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
> madvise_dontneed_free mm/madvise.c:940 [inline]
> madvise_vma_behavior mm/madvise.c:1270 [inline]
> madvise_walk_vmas mm/madvise.c:1502 [inline]
> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
> __do_sys_madvise mm/madvise.c:1705 [inline]
> __se_sys_madvise mm/madvise.c:1703 [inline]
> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> The buggy address belongs to the object at ffff888034718960
> which belongs to the cache page->ptl of size 64
> The buggy address is located 24 bytes inside of
> freed 64-byte region [ffff888034718960, ffff8880347189a0)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34718
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> page_type: f5(slab)
> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823, tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
> set_page_owner include/linux/page_owner.h:32 [inline]
> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
> prep_new_page mm/page_alloc.c:1557 [inline]
> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
> alloc_slab_page mm/slub.c:2408 [inline]
> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
> new_slab mm/slub.c:2627 [inline]
> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
> __slab_alloc+0x58/0xa0 mm/slub.c:3905
> __slab_alloc_node mm/slub.c:3980 [inline]
> slab_alloc_node mm/slub.c:4141 [inline]
> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
> ptlock_alloc mm/memory.c:7026 [inline]
> ptlock_init include/linux/mm.h:2971 [inline]
> pmd_ptlock_init include/linux/mm.h:3078 [inline]
> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
> pmd_alloc include/linux/mm.h:2862 [inline]
> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
> copy_pud_range mm/memory.c:1298 [inline]
> copy_p4d_range mm/memory.c:1322 [inline]
> copy_page_range+0x99f/0xe90 mm/memory.c:1420
> dup_mmap kernel/fork.c:751 [inline]
> dup_mm kernel/fork.c:1693 [inline]
> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
> copy_process+0x1845/0x3d80 kernel/fork.c:2393
> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
> __do_sys_clone kernel/fork.c:2948 [inline]
> __se_sys_clone kernel/fork.c:2932 [inline]
> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> page last free pid 6052 tgid 6051 stack trace:
> reset_page_owner include/linux/page_owner.h:25 [inline]
> free_pages_prepare mm/page_alloc.c:1127 [inline]
> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
> __folio_put+0x2b3/0x360 mm/swap.c:112
> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>
> Memory state around the buggy address:
> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
> ^
> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 6:25 ` Qi Zheng
@ 2024-12-09 6:48 ` Qi Zheng
2024-12-09 6:50 ` syzbot
2024-12-09 7:00 ` Qi Zheng
1 sibling, 1 reply; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 6:48 UTC (permalink / raw)
To: syzbot
Cc: David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song, akpm,
bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/9 14:25, Qi Zheng wrote:
>
>
> On 2024/12/8 01:14, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
>> git tree: linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
>> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for
>> Debian) 2.40
>> syz repro:
>> https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
>>
>> Downloadable assets:
>> disk image:
>> https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
>> vmlinux:
>> https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
>> kernel image:
>> https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
>>
>> The issue was bisected to:
>>
>> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
>> Author: Qi Zheng <zhengqi.arch@bytedance.com>
>> Date: Wed Dec 4 11:09:51 2024 +0000
>>
>> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
>>
>> bisection log:
>> https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
>> final oops:
>> https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the
>> commit:
>> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
>> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
>>
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100
>> kernel/locking/lockdep.c:5089
>> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
>>
>> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted
>> 6.13.0-rc1-next-20241205-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 09/13/2024
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:94 [inline]
>> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>> print_address_description mm/kasan/report.c:378 [inline]
>> print_report+0x169/0x550 mm/kasan/report.c:489
>> kasan_report+0x143/0x180 mm/kasan/report.c:602
>> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
>> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
>> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
>> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
>> spin_lock include/linux/spinlock.h:351 [inline]
>> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
>> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
>> userfaultfd_move fs/userfaultfd.c:1899 [inline]
>> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
>> vfs_ioctl fs/ioctl.c:51 [inline]
>> __do_sys_ioctl fs/ioctl.c:906 [inline]
>> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7fed8de85af9
>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48
>> 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
>> 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
>> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
>> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
>> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
>> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
>> </TASK>
>>
>> Allocated by task 6070:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> unpoison_slab_object mm/kasan/common.c:319 [inline]
>> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
>> kasan_slab_alloc include/linux/kasan.h:250 [inline]
>> slab_post_alloc_hook mm/slub.c:4104 [inline]
>> slab_alloc_node mm/slub.c:4153 [inline]
>> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
>> ptlock_alloc+0x20/0x70 mm/memory.c:7026
>> ptlock_init include/linux/mm.h:2971 [inline]
>> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
>> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
>> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
>> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
>> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
>> create_huge_pmd mm/memory.c:5737 [inline]
>> __handle_mm_fault mm/memory.c:5986 [inline]
>> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
>> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
>> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
>> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
>> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
>>
>> Freed by task 6071:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
>> poison_slab_object mm/kasan/common.c:247 [inline]
>> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
>> kasan_slab_free include/linux/kasan.h:233 [inline]
>> slab_free_hook mm/slub.c:2338 [inline]
>> slab_free mm/slub.c:4598 [inline]
>> kmem_cache_free+0x195/0x410 mm/slub.c:4700
>> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
>
> OK, so the problem is that ptdesc->ptl is not freed via RCU:
>
> ___pte_free_tlb
> --> pagetable_pte_dtor
> --> ptlock_free
> --> kmem_cache_free (free immediately!)
> paravirt_tlb_remove_table
> --> free PTE page via RCU
>
> In retract_page_tables(), it calls pte_free_defer() to free
> ptdesc->ptl and PTE page via RCU, so there is no problem.
>
> To fix it, will also free ptdesc->ptl in ptlock_free() via RCU.
>
>> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
>> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
>> free_pte+0x142/0x190 mm/pt_reclaim.c:31
>> zap_pte_range mm/memory.c:1780 [inline]
>> zap_pmd_range mm/memory.c:1822 [inline]
>> zap_pud_range mm/memory.c:1851 [inline]
>> zap_p4d_range mm/memory.c:1872 [inline]
>> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
>> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
>> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
>> madvise_dontneed_free mm/madvise.c:940 [inline]
>> madvise_vma_behavior mm/madvise.c:1270 [inline]
>> madvise_walk_vmas mm/madvise.c:1502 [inline]
>> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
>> __do_sys_madvise mm/madvise.c:1705 [inline]
>> __se_sys_madvise mm/madvise.c:1703 [inline]
>> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> The buggy address belongs to the object at ffff888034718960
>> which belongs to the cache page->ptl of size 64
>> The buggy address is located 24 bytes inside of
>> freed 64-byte region [ffff888034718960, ffff8880347189a0)
>>
>> The buggy address belongs to the physical page:
>> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
>> pfn:0x34718
>> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
>> page_type: f5(slab)
>> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
>> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
>> page dumped because: kasan: bad access detected
>> page_owner tracks the page as allocated
>> page last allocated via order 0, migratetype Unmovable, gfp_mask
>> 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823,
>> tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
>> set_page_owner include/linux/page_owner.h:32 [inline]
>> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
>> prep_new_page mm/page_alloc.c:1557 [inline]
>> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
>> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
>> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
>> alloc_slab_page mm/slub.c:2408 [inline]
>> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
>> new_slab mm/slub.c:2627 [inline]
>> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
>> __slab_alloc+0x58/0xa0 mm/slub.c:3905
>> __slab_alloc_node mm/slub.c:3980 [inline]
>> slab_alloc_node mm/slub.c:4141 [inline]
>> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
>> ptlock_alloc mm/memory.c:7026 [inline]
>> ptlock_init include/linux/mm.h:2971 [inline]
>> pmd_ptlock_init include/linux/mm.h:3078 [inline]
>> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
>> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
>> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
>> pmd_alloc include/linux/mm.h:2862 [inline]
>> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
>> copy_pud_range mm/memory.c:1298 [inline]
>> copy_p4d_range mm/memory.c:1322 [inline]
>> copy_page_range+0x99f/0xe90 mm/memory.c:1420
>> dup_mmap kernel/fork.c:751 [inline]
>> dup_mm kernel/fork.c:1693 [inline]
>> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
>> copy_process+0x1845/0x3d80 kernel/fork.c:2393
>> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
>> __do_sys_clone kernel/fork.c:2948 [inline]
>> __se_sys_clone kernel/fork.c:2932 [inline]
>> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> page last free pid 6052 tgid 6051 stack trace:
>> reset_page_owner include/linux/page_owner.h:25 [inline]
>> free_pages_prepare mm/page_alloc.c:1127 [inline]
>> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
>> __folio_put+0x2b3/0x360 mm/swap.c:112
>> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
>> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
>> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
>> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
>> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
>> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
>> __do_softirq kernel/softirq.c:595 [inline]
>> invoke_softirq kernel/softirq.c:435 [inline]
>> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
>> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
>> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049
>> [inline]
>> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
>> asm_sysvec_apic_timer_interrupt+0x1a/0x20
>> arch/x86/include/asm/idtentry.h:702
>>
>> Memory state around the buggy address:
>> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
>> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
>> ^
>> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
>> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>> ==================================================================
>>
>>
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@googlegroups.com.
>>
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>> For information about bisection process see:
>> https://goo.gl/tpsmEJ#bisection
>>
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>>
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
mm-unstable
diff --git a/mm/memory.c b/mm/memory.c
index 1fc1f14839916..15f058f5091b6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7014,7 +7014,7 @@ static struct kmem_cache *page_ptl_cachep;
void __init ptlock_cache_init(void)
{
page_ptl_cachep = kmem_cache_create("page->ptl",
sizeof(spinlock_t), 0,
- SLAB_PANIC, NULL);
+ SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
>>
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>>
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>>
>> If you want to undo deduplication, reply with:
>> #syz undup
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 6:48 ` Qi Zheng
@ 2024-12-09 6:50 ` syzbot
0 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2024-12-09 6:50 UTC (permalink / raw)
To: akpm, bp, dave.hansen, david, hpa, hughd, jannh, linux-kernel,
linux-mm, mingo, muchun.song, syzkaller-bugs, tglx, x86,
zhengqi.arch
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
failed to apply patch:
checking file mm/memory.c
Hunk #1 FAILED at 7014.
1 out of 1 hunk FAILED
Tested on:
commit: 6e165f54 mm/page_isolation: fixup isolate_single_pageb..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=13302b30580000
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 6:25 ` Qi Zheng
2024-12-09 6:48 ` Qi Zheng
@ 2024-12-09 7:00 ` Qi Zheng
2024-12-09 7:02 ` syzbot
2024-12-09 7:56 ` Yu Zhao
1 sibling, 2 replies; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 7:00 UTC (permalink / raw)
To: syzbot
Cc: David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song, akpm,
bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/9 14:25, Qi Zheng wrote:
>
>
> On 2024/12/8 01:14, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
>> git tree: linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
>> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for
>> Debian) 2.40
>> syz repro:
>> https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
>>
>> Downloadable assets:
>> disk image:
>> https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
>> vmlinux:
>> https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
>> kernel image:
>> https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
>>
>> The issue was bisected to:
>>
>> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
>> Author: Qi Zheng <zhengqi.arch@bytedance.com>
>> Date: Wed Dec 4 11:09:51 2024 +0000
>>
>> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
>>
>> bisection log:
>> https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
>> final oops:
>> https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the
>> commit:
>> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
>> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
>>
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100
>> kernel/locking/lockdep.c:5089
>> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
>>
>> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted
>> 6.13.0-rc1-next-20241205-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 09/13/2024
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:94 [inline]
>> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>> print_address_description mm/kasan/report.c:378 [inline]
>> print_report+0x169/0x550 mm/kasan/report.c:489
>> kasan_report+0x143/0x180 mm/kasan/report.c:602
>> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
>> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
>> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
>> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
>> spin_lock include/linux/spinlock.h:351 [inline]
>> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
>> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
>> userfaultfd_move fs/userfaultfd.c:1899 [inline]
>> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
>> vfs_ioctl fs/ioctl.c:51 [inline]
>> __do_sys_ioctl fs/ioctl.c:906 [inline]
>> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7fed8de85af9
>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48
>> 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
>> 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
>> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
>> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
>> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
>> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
>> </TASK>
>>
>> Allocated by task 6070:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> unpoison_slab_object mm/kasan/common.c:319 [inline]
>> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
>> kasan_slab_alloc include/linux/kasan.h:250 [inline]
>> slab_post_alloc_hook mm/slub.c:4104 [inline]
>> slab_alloc_node mm/slub.c:4153 [inline]
>> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
>> ptlock_alloc+0x20/0x70 mm/memory.c:7026
>> ptlock_init include/linux/mm.h:2971 [inline]
>> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
>> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
>> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
>> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
>> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
>> create_huge_pmd mm/memory.c:5737 [inline]
>> __handle_mm_fault mm/memory.c:5986 [inline]
>> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
>> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
>> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
>> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
>> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
>>
>> Freed by task 6071:
>> kasan_save_stack mm/kasan/common.c:47 [inline]
>> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
>> poison_slab_object mm/kasan/common.c:247 [inline]
>> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
>> kasan_slab_free include/linux/kasan.h:233 [inline]
>> slab_free_hook mm/slub.c:2338 [inline]
>> slab_free mm/slub.c:4598 [inline]
>> kmem_cache_free+0x195/0x410 mm/slub.c:4700
>> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
>
> OK, so the problem is that ptdesc->ptl is not freed via RCU:
>
> ___pte_free_tlb
> --> pagetable_pte_dtor
> --> ptlock_free
> --> kmem_cache_free (free immediately!)
> paravirt_tlb_remove_table
> --> free PTE page via RCU
>
> In retract_page_tables(), it calls pte_free_defer() to free
> ptdesc->ptl and PTE page via RCU, so there is no problem.
>
> To fix it, will also free ptdesc->ptl in ptlock_free() via RCU.
>
>> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
>> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
>> free_pte+0x142/0x190 mm/pt_reclaim.c:31
>> zap_pte_range mm/memory.c:1780 [inline]
>> zap_pmd_range mm/memory.c:1822 [inline]
>> zap_pud_range mm/memory.c:1851 [inline]
>> zap_p4d_range mm/memory.c:1872 [inline]
>> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
>> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
>> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
>> madvise_dontneed_free mm/madvise.c:940 [inline]
>> madvise_vma_behavior mm/madvise.c:1270 [inline]
>> madvise_walk_vmas mm/madvise.c:1502 [inline]
>> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
>> __do_sys_madvise mm/madvise.c:1705 [inline]
>> __se_sys_madvise mm/madvise.c:1703 [inline]
>> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> The buggy address belongs to the object at ffff888034718960
>> which belongs to the cache page->ptl of size 64
>> The buggy address is located 24 bytes inside of
>> freed 64-byte region [ffff888034718960, ffff8880347189a0)
>>
>> The buggy address belongs to the physical page:
>> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
>> pfn:0x34718
>> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
>> page_type: f5(slab)
>> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
>> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
>> page dumped because: kasan: bad access detected
>> page_owner tracks the page as allocated
>> page last allocated via order 0, migratetype Unmovable, gfp_mask
>> 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823,
>> tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
>> set_page_owner include/linux/page_owner.h:32 [inline]
>> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
>> prep_new_page mm/page_alloc.c:1557 [inline]
>> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
>> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
>> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
>> alloc_slab_page mm/slub.c:2408 [inline]
>> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
>> new_slab mm/slub.c:2627 [inline]
>> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
>> __slab_alloc+0x58/0xa0 mm/slub.c:3905
>> __slab_alloc_node mm/slub.c:3980 [inline]
>> slab_alloc_node mm/slub.c:4141 [inline]
>> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
>> ptlock_alloc mm/memory.c:7026 [inline]
>> ptlock_init include/linux/mm.h:2971 [inline]
>> pmd_ptlock_init include/linux/mm.h:3078 [inline]
>> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
>> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
>> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
>> pmd_alloc include/linux/mm.h:2862 [inline]
>> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
>> copy_pud_range mm/memory.c:1298 [inline]
>> copy_p4d_range mm/memory.c:1322 [inline]
>> copy_page_range+0x99f/0xe90 mm/memory.c:1420
>> dup_mmap kernel/fork.c:751 [inline]
>> dup_mm kernel/fork.c:1693 [inline]
>> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
>> copy_process+0x1845/0x3d80 kernel/fork.c:2393
>> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
>> __do_sys_clone kernel/fork.c:2948 [inline]
>> __se_sys_clone kernel/fork.c:2932 [inline]
>> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>> page last free pid 6052 tgid 6051 stack trace:
>> reset_page_owner include/linux/page_owner.h:25 [inline]
>> free_pages_prepare mm/page_alloc.c:1127 [inline]
>> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
>> __folio_put+0x2b3/0x360 mm/swap.c:112
>> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
>> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
>> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
>> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
>> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
>> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
>> __do_softirq kernel/softirq.c:595 [inline]
>> invoke_softirq kernel/softirq.c:435 [inline]
>> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
>> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
>> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049
>> [inline]
>> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
>> asm_sysvec_apic_timer_interrupt+0x1a/0x20
>> arch/x86/include/asm/idtentry.h:702
>>
>> Memory state around the buggy address:
>> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
>> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
>> ^
>> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
>> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>> ==================================================================
>>
>>
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@googlegroups.com.
>>
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>> For information about bisection process see:
>> https://goo.gl/tpsmEJ#bisection
>>
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>>
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
mm-unstable
diff --git a/mm/memory.c b/mm/memory.c
index 83fd35c034d7a..28526a4205d1b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7023,7 +7023,7 @@ static struct kmem_cache *page_ptl_cachep;
void __init ptlock_cache_init(void)
{
page_ptl_cachep = kmem_cache_create("page->ptl",
sizeof(spinlock_t), 0,
- SLAB_PANIC, NULL);
+ SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
>>
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>>
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>>
>> If you want to undo deduplication, reply with:
>> #syz undup
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 7:00 ` Qi Zheng
@ 2024-12-09 7:02 ` syzbot
2024-12-09 7:56 ` Yu Zhao
1 sibling, 0 replies; 14+ messages in thread
From: syzbot @ 2024-12-09 7:02 UTC (permalink / raw)
To: akpm, bp, dave.hansen, david, hpa, hughd, jannh, linux-kernel,
linux-mm, mingo, muchun.song, syzkaller-bugs, tglx, x86,
zhengqi.arch
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
failed to apply patch:
checking file mm/memory.c
Hunk #1 FAILED at 7023.
1 out of 1 hunk FAILED
Tested on:
commit: 6e165f54 mm/page_isolation: fixup isolate_single_pageb..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=135d94df980000
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-07 17:14 [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte syzbot
2024-12-09 6:25 ` Qi Zheng
@ 2024-12-09 7:33 ` Qi Zheng
2024-12-09 7:51 ` syzbot
2024-12-09 9:31 ` Qi Zheng
2 siblings, 1 reply; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 7:33 UTC (permalink / raw)
To: syzbot
Cc: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
[-- Attachment #1: Type: text/plain, Size: 11510 bytes --]
On 2024/12/8 01:14, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
> dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
>
> The issue was bisected to:
>
> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
> Author: Qi Zheng <zhengqi.arch@bytedance.com>
> Date: Wed Dec 4 11:09:51 2024 +0000
>
> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
>
> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0x169/0x550 mm/kasan/report.c:489
> kasan_report+0x143/0x180 mm/kasan/report.c:602
> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
> spin_lock include/linux/spinlock.h:351 [inline]
> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
> userfaultfd_move fs/userfaultfd.c:1899 [inline]
> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:906 [inline]
> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fed8de85af9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
> </TASK>
>
> Allocated by task 6070:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> unpoison_slab_object mm/kasan/common.c:319 [inline]
> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> slab_post_alloc_hook mm/slub.c:4104 [inline]
> slab_alloc_node mm/slub.c:4153 [inline]
> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
> ptlock_alloc+0x20/0x70 mm/memory.c:7026
> ptlock_init include/linux/mm.h:2971 [inline]
> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
> create_huge_pmd mm/memory.c:5737 [inline]
> __handle_mm_fault mm/memory.c:5986 [inline]
> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
>
> Freed by task 6071:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2338 [inline]
> slab_free mm/slub.c:4598 [inline]
> kmem_cache_free+0x195/0x410 mm/slub.c:4700
> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
> free_pte+0x142/0x190 mm/pt_reclaim.c:31
> zap_pte_range mm/memory.c:1780 [inline]
> zap_pmd_range mm/memory.c:1822 [inline]
> zap_pud_range mm/memory.c:1851 [inline]
> zap_p4d_range mm/memory.c:1872 [inline]
> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
> madvise_dontneed_free mm/madvise.c:940 [inline]
> madvise_vma_behavior mm/madvise.c:1270 [inline]
> madvise_walk_vmas mm/madvise.c:1502 [inline]
> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
> __do_sys_madvise mm/madvise.c:1705 [inline]
> __se_sys_madvise mm/madvise.c:1703 [inline]
> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> The buggy address belongs to the object at ffff888034718960
> which belongs to the cache page->ptl of size 64
> The buggy address is located 24 bytes inside of
> freed 64-byte region [ffff888034718960, ffff8880347189a0)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34718
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> page_type: f5(slab)
> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823, tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
> set_page_owner include/linux/page_owner.h:32 [inline]
> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
> prep_new_page mm/page_alloc.c:1557 [inline]
> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
> alloc_slab_page mm/slub.c:2408 [inline]
> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
> new_slab mm/slub.c:2627 [inline]
> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
> __slab_alloc+0x58/0xa0 mm/slub.c:3905
> __slab_alloc_node mm/slub.c:3980 [inline]
> slab_alloc_node mm/slub.c:4141 [inline]
> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
> ptlock_alloc mm/memory.c:7026 [inline]
> ptlock_init include/linux/mm.h:2971 [inline]
> pmd_ptlock_init include/linux/mm.h:3078 [inline]
> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
> pmd_alloc include/linux/mm.h:2862 [inline]
> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
> copy_pud_range mm/memory.c:1298 [inline]
> copy_p4d_range mm/memory.c:1322 [inline]
> copy_page_range+0x99f/0xe90 mm/memory.c:1420
> dup_mmap kernel/fork.c:751 [inline]
> dup_mm kernel/fork.c:1693 [inline]
> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
> copy_process+0x1845/0x3d80 kernel/fork.c:2393
> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
> __do_sys_clone kernel/fork.c:2948 [inline]
> __se_sys_clone kernel/fork.c:2932 [inline]
> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> page last free pid 6052 tgid 6051 stack trace:
> reset_page_owner include/linux/page_owner.h:25 [inline]
> free_pages_prepare mm/page_alloc.c:1127 [inline]
> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
> __folio_put+0x2b3/0x360 mm/swap.c:112
> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>
> Memory state around the buggy address:
> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
> ^
> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
mm-unstable
[-- Attachment #2: 0001-mm-pgtable-fix-UAF-of-ptdesc-ptl.patch --]
[-- Type: text/plain, Size: 5587 bytes --]
From 92942ffa57404ebbe9e8b3a5a74347adabb07cff Mon Sep 17 00:00:00 2001
From: Qi Zheng <zhengqi.arch@bytedance.com>
Date: Mon, 9 Dec 2024 15:10:17 +0800
Subject: [PATCH] mm: pgtable: fix UAF of ptdesc->ptl
The syzbot reported the following BUG:
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
__lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
userfaultfd_move fs/userfaultfd.c:1899 [inline]
userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed8de85af9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
</TASK>
Allocated by task 6070:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
ptlock_alloc+0x20/0x70 mm/memory.c:7026
ptlock_init include/linux/mm.h:2971 [inline]
pagetable_pte_ctor include/linux/mm.h:2998 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
__do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
create_huge_pmd mm/memory.c:5737 [inline]
__handle_mm_fault mm/memory.c:5986 [inline]
handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
Freed by task 6071:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2338 [inline]
slab_free mm/slub.c:4598 [inline]
kmem_cache_free+0x195/0x410 mm/slub.c:4700
pagetable_pte_dtor include/linux/mm.h:3009 [inline]
___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
__pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
free_pte+0x142/0x190 mm/pt_reclaim.c:31
zap_pte_range mm/memory.c:1780 [inline]
zap_pmd_range mm/memory.c:1822 [inline]
zap_pud_range mm/memory.c:1851 [inline]
zap_p4d_range mm/memory.c:1872 [inline]
unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
zap_page_range_single+0x45c/0x630 mm/memory.c:2018
madvise_dontneed_single_vma mm/madvise.c:859 [inline]
madvise_dontneed_free mm/madvise.c:940 [inline]
madvise_vma_behavior mm/madvise.c:1270 [inline]
madvise_walk_vmas mm/madvise.c:1502 [inline]
do_madvise+0x2774/0x4d90 mm/madvise.c:1689
__do_sys_madvise mm/madvise.c:1705 [inline]
__se_sys_madvise mm/madvise.c:1703 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
To fix, enable SLAB_TYPESAFE_BY_RCU for page_ptl_cachep.
Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index 83fd35c034d7a..28526a4205d1b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7023,7 +7023,7 @@ static struct kmem_cache *page_ptl_cachep;
void __init ptlock_cache_init(void)
{
page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
- SLAB_PANIC, NULL);
+ SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
--
2.20.1
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 7:33 ` Qi Zheng
@ 2024-12-09 7:51 ` syzbot
2024-12-09 7:58 ` Qi Zheng
0 siblings, 1 reply; 14+ messages in thread
From: syzbot @ 2024-12-09 7:51 UTC (permalink / raw)
To: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86, zhengqi.arch
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in move_pages_pte
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6741 at mm/userfaultfd.c:1188 move_pages_pte+0x26bb/0x3400 mm/userfaultfd.c:1188
Modules linked in:
CPU: 0 UID: 0 PID: 6741 Comm: syz.0.36 Not tainted 6.13.0-rc1-syzkaller-00172-g6e165f544379-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:move_pages_pte+0x26bb/0x3400 mm/userfaultfd.c:1188
Code: 8d ff b8 f5 ff ff ff e9 f9 f1 ff ff e8 de 41 8d ff 90 0f 0b 90 b8 ea ff ff ff 48 89 44 24 18 e9 9a fb ff ff e8 c6 41 8d ff 90 <0f> 0b 90 eb 14 e8 bb 41 8d ff 90 0f 0b 90 eb 09 e8 b0 41 8d ff 90
RSP: 0018:ffffc900034871c0 EFLAGS: 00010293
RAX: ffffffff8212016a RBX: 0000000000000000 RCX: ffff88801fbb9e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003487600 R08: ffffffff8211df31 R09: 1ffffffff2853d10
R10: dffffc0000000000 R11: fffffbfff2853d11 R12: dffffc0000000000
R13: 0000000000000000 R14: 00000000321be067 R15: 0000000000000000
FS: 00007fd136ec86c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd136ea6fb8 CR3: 0000000031194000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
move_pages+0xdd7/0x1600 mm/userfaultfd.c:1742
userfaultfd_move fs/userfaultfd.c:1899 [inline]
userfaultfd_ioctl+0x518b/0x6770 fs/userfaultfd.c:2022
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd13617ff19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd136ec8058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd136345fa0 RCX: 00007fd13617ff19
RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
RBP: 00007fd1361f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd136345fa0 R15: 00007ffd06723498
</TASK>
Tested on:
commit: 6e165f54 mm/page_isolation: fixup isolate_single_pageb..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
console output: https://syzkaller.appspot.com/x/log.txt?x=14142b30580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3884fb5fa6f2533c
dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=11245944580000
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 7:00 ` Qi Zheng
2024-12-09 7:02 ` syzbot
@ 2024-12-09 7:56 ` Yu Zhao
2024-12-09 8:09 ` Qi Zheng
1 sibling, 1 reply; 14+ messages in thread
From: Yu Zhao @ 2024-12-09 7:56 UTC (permalink / raw)
To: Qi Zheng
Cc: syzbot, David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song,
akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On Mon, Dec 9, 2024 at 12:00 AM Qi Zheng <zhengqi.arch@bytedance.com> wrote:
>
>
>
> On 2024/12/9 14:25, Qi Zheng wrote:
> >
> >
> > On 2024/12/8 01:14, syzbot wrote:
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
> >> git tree: linux-next
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
> >> kernel config:
> >> https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
> >> dashboard link:
> >> https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
> >> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for
> >> Debian) 2.40
> >> syz repro:
> >> https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
> >>
> >> Downloadable assets:
> >> disk image:
> >> https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
> >> vmlinux:
> >> https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
> >> kernel image:
> >> https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
> >>
> >> The issue was bisected to:
> >>
> >> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
> >> Author: Qi Zheng <zhengqi.arch@bytedance.com>
> >> Date: Wed Dec 4 11:09:51 2024 +0000
> >>
> >> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
> >>
> >> bisection log:
> >> https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
> >> final oops:
> >> https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the
> >> commit:
> >> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
> >> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
> >>
> >> ==================================================================
> >> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100
> >> kernel/locking/lockdep.c:5089
> >> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
> >>
> >> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted
> >> 6.13.0-rc1-next-20241205-syzkaller #0
> >> Hardware name: Google Google Compute Engine/Google Compute Engine,
> >> BIOS Google 09/13/2024
> >> Call Trace:
> >> <TASK>
> >> __dump_stack lib/dump_stack.c:94 [inline]
> >> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> >> print_address_description mm/kasan/report.c:378 [inline]
> >> print_report+0x169/0x550 mm/kasan/report.c:489
> >> kasan_report+0x143/0x180 mm/kasan/report.c:602
> >> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> >> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
> >> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
> >> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
> >> spin_lock include/linux/spinlock.h:351 [inline]
> >> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
> >> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
> >> userfaultfd_move fs/userfaultfd.c:1899 [inline]
> >> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
> >> vfs_ioctl fs/ioctl.c:51 [inline]
> >> __do_sys_ioctl fs/ioctl.c:906 [inline]
> >> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
> >> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> >> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >> RIP: 0033:0x7fed8de85af9
> >> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48
> >> 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
> >> 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> >> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> >> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
> >> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
> >> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
> >> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
> >> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
> >> </TASK>
> >>
> >> Allocated by task 6070:
> >> kasan_save_stack mm/kasan/common.c:47 [inline]
> >> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> >> unpoison_slab_object mm/kasan/common.c:319 [inline]
> >> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
> >> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> >> slab_post_alloc_hook mm/slub.c:4104 [inline]
> >> slab_alloc_node mm/slub.c:4153 [inline]
> >> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
> >> ptlock_alloc+0x20/0x70 mm/memory.c:7026
> >> ptlock_init include/linux/mm.h:2971 [inline]
> >> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
> >> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
> >> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
> >> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
> >> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
> >> create_huge_pmd mm/memory.c:5737 [inline]
> >> __handle_mm_fault mm/memory.c:5986 [inline]
> >> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
> >> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
> >> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
> >> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
> >> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
> >>
> >> Freed by task 6071:
> >> kasan_save_stack mm/kasan/common.c:47 [inline]
> >> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> >> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> >> poison_slab_object mm/kasan/common.c:247 [inline]
> >> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> >> kasan_slab_free include/linux/kasan.h:233 [inline]
> >> slab_free_hook mm/slub.c:2338 [inline]
> >> slab_free mm/slub.c:4598 [inline]
> >> kmem_cache_free+0x195/0x410 mm/slub.c:4700
> >> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
> >
> > OK, so the problem is that ptdesc->ptl is not freed via RCU:
> >
> > ___pte_free_tlb
> > --> pagetable_pte_dtor
> > --> ptlock_free
> > --> kmem_cache_free (free immediately!)
> > paravirt_tlb_remove_table
> > --> free PTE page via RCU
> >
> > In retract_page_tables(), it calls pte_free_defer() to free
> > ptdesc->ptl and PTE page via RCU, so there is no problem.
> >
> > To fix it, will also free ptdesc->ptl in ptlock_free() via RCU.
> >
> >> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
> >> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
> >> free_pte+0x142/0x190 mm/pt_reclaim.c:31
> >> zap_pte_range mm/memory.c:1780 [inline]
> >> zap_pmd_range mm/memory.c:1822 [inline]
> >> zap_pud_range mm/memory.c:1851 [inline]
> >> zap_p4d_range mm/memory.c:1872 [inline]
> >> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
> >> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
> >> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
> >> madvise_dontneed_free mm/madvise.c:940 [inline]
> >> madvise_vma_behavior mm/madvise.c:1270 [inline]
> >> madvise_walk_vmas mm/madvise.c:1502 [inline]
> >> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
> >> __do_sys_madvise mm/madvise.c:1705 [inline]
> >> __se_sys_madvise mm/madvise.c:1703 [inline]
> >> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
> >> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> >> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >>
> >> The buggy address belongs to the object at ffff888034718960
> >> which belongs to the cache page->ptl of size 64
> >> The buggy address is located 24 bytes inside of
> >> freed 64-byte region [ffff888034718960, ffff8880347189a0)
> >>
> >> The buggy address belongs to the physical page:
> >> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
> >> pfn:0x34718
> >> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> >> page_type: f5(slab)
> >> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
> >> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
> >> page dumped because: kasan: bad access detected
> >> page_owner tracks the page as allocated
> >> page last allocated via order 0, migratetype Unmovable, gfp_mask
> >> 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823,
> >> tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
> >> set_page_owner include/linux/page_owner.h:32 [inline]
> >> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
> >> prep_new_page mm/page_alloc.c:1557 [inline]
> >> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
> >> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
> >> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
> >> alloc_slab_page mm/slub.c:2408 [inline]
> >> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
> >> new_slab mm/slub.c:2627 [inline]
> >> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
> >> __slab_alloc+0x58/0xa0 mm/slub.c:3905
> >> __slab_alloc_node mm/slub.c:3980 [inline]
> >> slab_alloc_node mm/slub.c:4141 [inline]
> >> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
> >> ptlock_alloc mm/memory.c:7026 [inline]
> >> ptlock_init include/linux/mm.h:2971 [inline]
> >> pmd_ptlock_init include/linux/mm.h:3078 [inline]
> >> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
> >> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
> >> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
> >> pmd_alloc include/linux/mm.h:2862 [inline]
> >> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
> >> copy_pud_range mm/memory.c:1298 [inline]
> >> copy_p4d_range mm/memory.c:1322 [inline]
> >> copy_page_range+0x99f/0xe90 mm/memory.c:1420
> >> dup_mmap kernel/fork.c:751 [inline]
> >> dup_mm kernel/fork.c:1693 [inline]
> >> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
> >> copy_process+0x1845/0x3d80 kernel/fork.c:2393
> >> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
> >> __do_sys_clone kernel/fork.c:2948 [inline]
> >> __se_sys_clone kernel/fork.c:2932 [inline]
> >> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
> >> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> >> page last free pid 6052 tgid 6051 stack trace:
> >> reset_page_owner include/linux/page_owner.h:25 [inline]
> >> free_pages_prepare mm/page_alloc.c:1127 [inline]
> >> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
> >> __folio_put+0x2b3/0x360 mm/swap.c:112
> >> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
> >> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
> >> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
> >> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> >> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
> >> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> >> __do_softirq kernel/softirq.c:595 [inline]
> >> invoke_softirq kernel/softirq.c:435 [inline]
> >> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> >> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> >> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049
> >> [inline]
> >> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> >> asm_sysvec_apic_timer_interrupt+0x1a/0x20
> >> arch/x86/include/asm/idtentry.h:702
> >>
> >> Memory state around the buggy address:
> >> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
> >> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
> >>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
> >> ^
> >> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
> >> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
> >> ==================================================================
> >>
> >>
> >> ---
> >> This report is generated by a bot. It may contain errors.
> >> See https://goo.gl/tpsmEJ for more information about syzbot.
> >> syzbot engineers can be reached at syzkaller@googlegroups.com.
> >>
> >> syzbot will keep track of this issue. See:
> >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >> For information about bisection process see:
> >> https://goo.gl/tpsmEJ#bisection
> >>
> >> If the report is already addressed, let syzbot know by replying with:
> >> #syz fix: exact-commit-title
> >>
> >> If you want syzbot to run the reproducer, reply with:
> >> #syz test: git://repo/address.git branch-or-commit-hash
> >> If you attach or paste a git patch, syzbot will apply it before testing.
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
> mm-unstable
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 83fd35c034d7a..28526a4205d1b 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -7023,7 +7023,7 @@ static struct kmem_cache *page_ptl_cachep;
> void __init ptlock_cache_init(void)
> {
> page_ptl_cachep = kmem_cache_create("page->ptl",
> sizeof(spinlock_t), 0,
> - SLAB_PANIC, NULL);
> + SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
Note that `SLAB_TYPESAFE_BY_RCU` works by freeing the entire slab (the
page containing the objects) with RCU, not individual objects.
So I don't think this would work. A PTL object can be re-allocated to
someone else, and that new user can re-initialize it. So trying to
concurrently lock it under RCU read lock would also be use-after-free.
> }
>
> bool ptlock_alloc(struct ptdesc *ptdesc)
>
> >>
> >> If you want to overwrite report's subsystems, reply with:
> >> #syz set subsystems: new-subsystem
> >> (See the list of subsystem names on the web dashboard)
> >>
> >> If the report is a duplicate of another one, reply with:
> >> #syz dup: exact-subject-of-another-report
> >>
> >> If you want to undo deduplication, reply with:
> >> #syz undup
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 7:51 ` syzbot
@ 2024-12-09 7:58 ` Qi Zheng
0 siblings, 0 replies; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 7:58 UTC (permalink / raw)
To: syzbot
Cc: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/9 15:51, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> WARNING in move_pages_pte
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 6741 at mm/userfaultfd.c:1188 move_pages_pte+0x26bb/0x3400 mm/userfaultfd.c:1188
The code of triggering warning is as follows:
/* Sanity checks before the operation */
if (WARN_ON_ONCE(pmd_none(*dst_pmd)) || WARN_ON_ONCE(pmd_none(*src_pmd)) ||
WARN_ON_ONCE(pmd_trans_huge(*dst_pmd)) ||
WARN_ON_ONCE(pmd_trans_huge(*src_pmd))) {
err = -EINVAL;
goto out;
}
This is expected, we can just remove these WARN_ON_ONCE().
> Modules linked in:
> CPU: 0 UID: 0 PID: 6741 Comm: syz.0.36 Not tainted 6.13.0-rc1-syzkaller-00172-g6e165f544379-dirty #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> RIP: 0010:move_pages_pte+0x26bb/0x3400 mm/userfaultfd.c:1188
> Code: 8d ff b8 f5 ff ff ff e9 f9 f1 ff ff e8 de 41 8d ff 90 0f 0b 90 b8 ea ff ff ff 48 89 44 24 18 e9 9a fb ff ff e8 c6 41 8d ff 90 <0f> 0b 90 eb 14 e8 bb 41 8d ff 90 0f 0b 90 eb 09 e8 b0 41 8d ff 90
> RSP: 0018:ffffc900034871c0 EFLAGS: 00010293
> RAX: ffffffff8212016a RBX: 0000000000000000 RCX: ffff88801fbb9e00
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc90003487600 R08: ffffffff8211df31 R09: 1ffffffff2853d10
> R10: dffffc0000000000 R11: fffffbfff2853d11 R12: dffffc0000000000
> R13: 0000000000000000 R14: 00000000321be067 R15: 0000000000000000
> FS: 00007fd136ec86c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fd136ea6fb8 CR3: 0000000031194000 CR4: 00000000003526f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> move_pages+0xdd7/0x1600 mm/userfaultfd.c:1742
> userfaultfd_move fs/userfaultfd.c:1899 [inline]
> userfaultfd_ioctl+0x518b/0x6770 fs/userfaultfd.c:2022
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:906 [inline]
> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fd13617ff19
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fd136ec8058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fd136345fa0 RCX: 00007fd13617ff19
> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
> RBP: 00007fd1361f3986 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007fd136345fa0 R15: 00007ffd06723498
> </TASK>
>
>
> Tested on:
>
> commit: 6e165f54 mm/page_isolation: fixup isolate_single_pageb..
> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> console output: https://syzkaller.appspot.com/x/log.txt?x=14142b30580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3884fb5fa6f2533c
> dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> patch: https://syzkaller.appspot.com/x/patch.diff?x=11245944580000
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 7:56 ` Yu Zhao
@ 2024-12-09 8:09 ` Qi Zheng
2024-12-09 9:20 ` Qi Zheng
0 siblings, 1 reply; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 8:09 UTC (permalink / raw)
To: Yu Zhao
Cc: syzbot, David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song,
akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/9 15:56, Yu Zhao wrote:
> On Mon, Dec 9, 2024 at 12:00 AM Qi Zheng <zhengqi.arch@bytedance.com> wrote:
[...]
>>>>
>>>> If you want syzbot to run the reproducer, reply with:
>>>> #syz test: git://repo/address.git branch-or-commit-hash
>>>> If you attach or paste a git patch, syzbot will apply it before testing.
>>
>> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
>> mm-unstable
>>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 83fd35c034d7a..28526a4205d1b 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -7023,7 +7023,7 @@ static struct kmem_cache *page_ptl_cachep;
>> void __init ptlock_cache_init(void)
>> {
>> page_ptl_cachep = kmem_cache_create("page->ptl",
>> sizeof(spinlock_t), 0,
>> - SLAB_PANIC, NULL);
>> + SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
>
> Note that `SLAB_TYPESAFE_BY_RCU` works by freeing the entire slab (the
> page containing the objects) with RCU, not individual objects.
>
> So I don't think this would work. A PTL object can be re-allocated to
> someone else, and that new user can re-initialize it. So trying to
> concurrently lock it under RCU read lock would also be use-after-free.
>
Got it. Thanks for pointing this out! So we should put ptlock_free()
into the RCU callback instead of enabling SLAB_TYPESAFE_BY_RCU for
page_ptl_cachep.
>>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 8:09 ` Qi Zheng
@ 2024-12-09 9:20 ` Qi Zheng
0 siblings, 0 replies; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 9:20 UTC (permalink / raw)
To: Yu Zhao
Cc: syzbot, David Hildenbrand, Jann Horn, Hugh Dickins, Muchun Song,
akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
On 2024/12/9 16:09, Qi Zheng wrote:
>
>
> On 2024/12/9 15:56, Yu Zhao wrote:
>> On Mon, Dec 9, 2024 at 12:00 AM Qi Zheng <zhengqi.arch@bytedance.com>
>> wrote:
>
> [...]
>
>>>>>
>>>>> If you want syzbot to run the reproducer, reply with:
>>>>> #syz test: git://repo/address.git branch-or-commit-hash
>>>>> If you attach or paste a git patch, syzbot will apply it before
>>>>> testing.
>>>
>>> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
>>> mm-unstable
>>>
>>> diff --git a/mm/memory.c b/mm/memory.c
>>> index 83fd35c034d7a..28526a4205d1b 100644
>>> --- a/mm/memory.c
>>> +++ b/mm/memory.c
>>> @@ -7023,7 +7023,7 @@ static struct kmem_cache *page_ptl_cachep;
>>> void __init ptlock_cache_init(void)
>>> {
>>> page_ptl_cachep = kmem_cache_create("page->ptl",
>>> sizeof(spinlock_t), 0,
>>> - SLAB_PANIC, NULL);
>>> + SLAB_PANIC|SLAB_TYPESAFE_BY_RCU, NULL);
>>
>> Note that `SLAB_TYPESAFE_BY_RCU` works by freeing the entire slab (the
>> page containing the objects) with RCU, not individual objects.
>>
>> So I don't think this would work. A PTL object can be re-allocated to
>> someone else, and that new user can re-initialize it. So trying to
>> concurrently lock it under RCU read lock would also be use-after-free.
>>
>
> Got it. Thanks for pointing this out! So we should put ptlock_free()
> into the RCU callback instead of enabling SLAB_TYPESAFE_BY_RCU for
> page_ptl_cachep.
Like the following:
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 95bfaf5b85d90..b532415ef5841 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2988,7 +2988,7 @@ void ptlock_free(struct ptdesc *ptdesc);
static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
{
- return ptdesc->ptl;
+ return &(ptdesc->ptl->ptl);
}
#else /* ALLOC_SPLIT_PTLOCKS */
static inline void ptlock_cache_init(void)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d0e720ccecd71..7b94ea4d0d26a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -434,6 +434,13 @@ FOLIO_MATCH(flags, _flags_2a);
FOLIO_MATCH(compound_head, _head_2a);
#undef FOLIO_MATCH
+#if ALLOC_SPLIT_PTLOCKS
+struct pt_lock {
+ spinlock_t ptl;
+ struct rcu_head rcu;
+};
+#endif
+
/**
* struct ptdesc - Memory descriptor for page tables.
* @__page_flags: Same as page flags. Powerpc only.
@@ -478,7 +485,7 @@ struct ptdesc {
union {
unsigned long _pt_pad_2;
#if ALLOC_SPLIT_PTLOCKS
- spinlock_t *ptl;
+ struct pt_lock *ptl;
#else
spinlock_t ptl;
#endif
diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h
index a82aa80c0ba46..774ef2a128104 100644
--- a/include/linux/mm_types_task.h
+++ b/include/linux/mm_types_task.h
@@ -17,7 +17,8 @@
#include <asm/tlbbatch.h>
#endif
-#define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
+/*#define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)*/
+#define ALLOC_SPLIT_PTLOCKS 1
/*
* When updating this, please also update struct resident_page_types[] in
diff --git a/mm/memory.c b/mm/memory.c
index 83fd35c034d7a..802dae0602b32 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7022,24 +7022,34 @@ static struct kmem_cache *page_ptl_cachep;
void __init ptlock_cache_init(void)
{
- page_ptl_cachep = kmem_cache_create("page->ptl",
sizeof(spinlock_t), 0,
+ page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(struct
pt_lock), 0,
SLAB_PANIC, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
{
- spinlock_t *ptl;
+ struct pt_lock *pt_lock;
- ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
- if (!ptl)
+ pt_lock = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
+ if (!pt_lock)
return false;
- ptdesc->ptl = ptl;
+ ptdesc->ptl = pt_lock;
return true;
}
+static void ptlock_free_rcu(struct rcu_head *head)
+{
+ struct pt_lock *pt_lock;
+
+ pt_lock = container_of(head, struct pt_lock, rcu);
+ kmem_cache_free(page_ptl_cachep, pt_lock);
+}
+
void ptlock_free(struct ptdesc *ptdesc)
{
- kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
+ struct pt_lock *pt_lock = ptdesc->ptl;
+
+ call_rcu(&pt_lock->rcu, ptlock_free_rcu);
}
#endif
>
>>>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-07 17:14 [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte syzbot
2024-12-09 6:25 ` Qi Zheng
2024-12-09 7:33 ` Qi Zheng
@ 2024-12-09 9:31 ` Qi Zheng
2024-12-09 11:39 ` syzbot
2 siblings, 1 reply; 14+ messages in thread
From: Qi Zheng @ 2024-12-09 9:31 UTC (permalink / raw)
To: syzbot
Cc: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86
[-- Attachment #1: Type: text/plain, Size: 11514 bytes --]
On 2024/12/8 01:14, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: af2ea8ab7a54 Add linux-next specific files for 20241205
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13c4e8df980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=76f158395f6f15fd
> dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133850f8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17be9330580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/8af0861258fa/disk-af2ea8ab.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ffb38cf7a344/vmlinux-af2ea8ab.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/6fbd2e50358a/bzImage-af2ea8ab.xz
>
> The issue was bisected to:
>
> commit 5b29c4156f5801fced2ec504b44ab98f60c480bf
> Author: Qi Zheng <zhengqi.arch@bytedance.com>
> Date: Wed Dec 4 11:09:51 2024 +0000
>
> x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d344df980000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=15d344df980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=11d344df980000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
> Fixes: 5b29c4156f58 ("x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64")
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
>
> CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0x169/0x550 mm/kasan/report.c:489
> kasan_report+0x143/0x180 mm/kasan/report.c:602
> __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
> __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
> _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
> spin_lock include/linux/spinlock.h:351 [inline]
> move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
> move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
> userfaultfd_move fs/userfaultfd.c:1899 [inline]
> userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:906 [inline]
> __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fed8de85af9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
> RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
> RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
> R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
> R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
> </TASK>
>
> Allocated by task 6070:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> unpoison_slab_object mm/kasan/common.c:319 [inline]
> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> slab_post_alloc_hook mm/slub.c:4104 [inline]
> slab_alloc_node mm/slub.c:4153 [inline]
> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
> ptlock_alloc+0x20/0x70 mm/memory.c:7026
> ptlock_init include/linux/mm.h:2971 [inline]
> pagetable_pte_ctor include/linux/mm.h:2998 [inline]
> __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
> pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
> __do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
> do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
> create_huge_pmd mm/memory.c:5737 [inline]
> __handle_mm_fault mm/memory.c:5986 [inline]
> handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
> do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
> handle_page_fault arch/x86/mm/fault.c:1481 [inline]
> exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
>
> Freed by task 6071:
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2338 [inline]
> slab_free mm/slub.c:4598 [inline]
> kmem_cache_free+0x195/0x410 mm/slub.c:4700
> pagetable_pte_dtor include/linux/mm.h:3009 [inline]
> ___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
> __pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
> free_pte+0x142/0x190 mm/pt_reclaim.c:31
> zap_pte_range mm/memory.c:1780 [inline]
> zap_pmd_range mm/memory.c:1822 [inline]
> zap_pud_range mm/memory.c:1851 [inline]
> zap_p4d_range mm/memory.c:1872 [inline]
> unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
> zap_page_range_single+0x45c/0x630 mm/memory.c:2018
> madvise_dontneed_single_vma mm/madvise.c:859 [inline]
> madvise_dontneed_free mm/madvise.c:940 [inline]
> madvise_vma_behavior mm/madvise.c:1270 [inline]
> madvise_walk_vmas mm/madvise.c:1502 [inline]
> do_madvise+0x2774/0x4d90 mm/madvise.c:1689
> __do_sys_madvise mm/madvise.c:1705 [inline]
> __se_sys_madvise mm/madvise.c:1703 [inline]
> __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> The buggy address belongs to the object at ffff888034718960
> which belongs to the cache page->ptl of size 64
> The buggy address is located 24 bytes inside of
> freed 64-byte region [ffff888034718960, ffff8880347189a0)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34718
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> page_type: f5(slab)
> raw: 00fff00000000000 ffff88801ac4f780 dead000000000122 0000000000000000
> raw: 0000000000000000 00000000802a002a 00000000f5000000 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5823, tgid 5823 (syz-executor352), ts 65548803787, free_ts 65433386693
> set_page_owner include/linux/page_owner.h:32 [inline]
> post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1549
> prep_new_page mm/page_alloc.c:1557 [inline]
> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3475
> __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4752
> alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
> alloc_slab_page mm/slub.c:2408 [inline]
> allocate_slab+0x8f/0x3a0 mm/slub.c:2574
> new_slab mm/slub.c:2627 [inline]
> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
> __slab_alloc+0x58/0xa0 mm/slub.c:3905
> __slab_alloc_node mm/slub.c:3980 [inline]
> slab_alloc_node mm/slub.c:4141 [inline]
> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
> ptlock_alloc mm/memory.c:7026 [inline]
> ptlock_init include/linux/mm.h:2971 [inline]
> pmd_ptlock_init include/linux/mm.h:3078 [inline]
> pagetable_pmd_ctor include/linux/mm.h:3116 [inline]
> pmd_alloc_one_noprof include/asm-generic/pgalloc.h:141 [inline]
> __pmd_alloc+0x10b/0x670 mm/memory.c:6436
> pmd_alloc include/linux/mm.h:2862 [inline]
> copy_pmd_range+0x7352/0x77a0 mm/memory.c:1241
> copy_pud_range mm/memory.c:1298 [inline]
> copy_p4d_range mm/memory.c:1322 [inline]
> copy_page_range+0x99f/0xe90 mm/memory.c:1420
> dup_mmap kernel/fork.c:751 [inline]
> dup_mm kernel/fork.c:1693 [inline]
> copy_mm+0x12d2/0x2060 kernel/fork.c:1742
> copy_process+0x1845/0x3d80 kernel/fork.c:2393
> kernel_clone+0x226/0x8e0 kernel/fork.c:2805
> __do_sys_clone kernel/fork.c:2948 [inline]
> __se_sys_clone kernel/fork.c:2932 [inline]
> __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2932
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> page last free pid 6052 tgid 6051 stack trace:
> reset_page_owner include/linux/page_owner.h:25 [inline]
> free_pages_prepare mm/page_alloc.c:1127 [inline]
> free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2658
> __folio_put+0x2b3/0x360 mm/swap.c:112
> __tlb_remove_table arch/x86/include/asm/tlb.h:34 [inline]
> __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
> tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>
> Memory state around the buggy address:
> ffff888034718800: 00 00 00 00 fc fc fc fc 00 00 00 00 00 00 00 00
> ffff888034718880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
>> ffff888034718900: 00 00 00 00 00 00 00 00 fc fc fc fc fa fb fb fb
> ^
> ffff888034718980: fb fb fb fb fc fc fc fc fa fb fb fb fb fb fb fb
> ffff888034718a00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
mm-unstable
[-- Attachment #2: 0001-mm-pgtable-fix-UAF-of-ptdesc-ptl.patch --]
[-- Type: text/plain, Size: 8096 bytes --]
From 23c2fe376a7438568022845b0374c195e1db9c4e Mon Sep 17 00:00:00 2001
From: Qi Zheng <zhengqi.arch@bytedance.com>
Date: Mon, 9 Dec 2024 17:28:02 +0800
Subject: [PATCH] mm: pgtable: fix UAF of ptdesc->ptl
The syzbot reported the following BUG:
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
Read of size 8 at addr ffff888034718978 by task syz-executor352/6070
CPU: 0 UID: 0 PID: 6070 Comm: syz-executor352 Not tainted 6.13.0-rc1-next-20241205-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
__lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
move_pages_pte+0x8aa/0x3400 mm/userfaultfd.c:1248
move_pages+0xe75/0x16a0 mm/userfaultfd.c:1754
userfaultfd_move fs/userfaultfd.c:1899 [inline]
userfaultfd_ioctl+0x5221/0x6840 fs/userfaultfd.c:2022
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed8de85af9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed8de40238 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed8df10328 RCX: 00007fed8de85af9
RDX: 0000000020000080 RSI: 00000000c028aa05 RDI: 0000000000000003
RBP: 00007fed8df10320 R08: 00007fed8de406c0 R09: 00007fed8de406c0
R10: 00007fed8de406c0 R11: 0000000000000246 R12: 00007fed8dedd334
R13: 0000000000000010 R14: 00007ffc241241e0 R15: 00007ffc241242c8
</TASK>
Allocated by task 6070:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
ptlock_alloc+0x20/0x70 mm/memory.c:7026
ptlock_init include/linux/mm.h:2971 [inline]
pagetable_pte_ctor include/linux/mm.h:2998 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
pte_alloc_one+0xd3/0x510 arch/x86/mm/pgtable.c:41
__do_huge_pmd_anonymous_page mm/huge_memory.c:1229 [inline]
do_huge_pmd_anonymous_page+0x2fb/0xb30 mm/huge_memory.c:1374
create_huge_pmd mm/memory.c:5737 [inline]
__handle_mm_fault mm/memory.c:5986 [inline]
handle_mm_fault+0x15a7/0x1bb0 mm/memory.c:6183
do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
Freed by task 6071:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2338 [inline]
slab_free mm/slub.c:4598 [inline]
kmem_cache_free+0x195/0x410 mm/slub.c:4700
pagetable_pte_dtor include/linux/mm.h:3009 [inline]
___pte_free_tlb+0x2b/0x140 arch/x86/mm/pgtable.c:63
__pte_free_tlb arch/x86/include/asm/pgalloc.h:61 [inline]
free_pte+0x142/0x190 mm/pt_reclaim.c:31
zap_pte_range mm/memory.c:1780 [inline]
zap_pmd_range mm/memory.c:1822 [inline]
zap_pud_range mm/memory.c:1851 [inline]
zap_p4d_range mm/memory.c:1872 [inline]
unmap_page_range+0x4062/0x48d0 mm/memory.c:1893
zap_page_range_single+0x45c/0x630 mm/memory.c:2018
madvise_dontneed_single_vma mm/madvise.c:859 [inline]
madvise_dontneed_free mm/madvise.c:940 [inline]
madvise_vma_behavior mm/madvise.c:1270 [inline]
madvise_walk_vmas mm/madvise.c:1502 [inline]
do_madvise+0x2774/0x4d90 mm/madvise.c:1689
__do_sys_madvise mm/madvise.c:1705 [inline]
__se_sys_madvise mm/madvise.c:1703 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1703
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
To fix it, free ptdesc->ptl by RCU.
Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
include/linux/mm.h | 2 +-
include/linux/mm_types.h | 9 ++++++++-
mm/memory.c | 22 ++++++++++++++++------
mm/userfaultfd.c | 4 ++--
4 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 95bfaf5b85d90..b532415ef5841 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2988,7 +2988,7 @@ void ptlock_free(struct ptdesc *ptdesc);
static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
{
- return ptdesc->ptl;
+ return &(ptdesc->ptl->ptl);
}
#else /* ALLOC_SPLIT_PTLOCKS */
static inline void ptlock_cache_init(void)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d0e720ccecd71..7b94ea4d0d26a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -434,6 +434,13 @@ FOLIO_MATCH(flags, _flags_2a);
FOLIO_MATCH(compound_head, _head_2a);
#undef FOLIO_MATCH
+#if ALLOC_SPLIT_PTLOCKS
+struct pt_lock {
+ spinlock_t ptl;
+ struct rcu_head rcu;
+};
+#endif
+
/**
* struct ptdesc - Memory descriptor for page tables.
* @__page_flags: Same as page flags. Powerpc only.
@@ -478,7 +485,7 @@ struct ptdesc {
union {
unsigned long _pt_pad_2;
#if ALLOC_SPLIT_PTLOCKS
- spinlock_t *ptl;
+ struct pt_lock *ptl;
#else
spinlock_t ptl;
#endif
diff --git a/mm/memory.c b/mm/memory.c
index 83fd35c034d7a..802dae0602b32 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -7022,24 +7022,34 @@ static struct kmem_cache *page_ptl_cachep;
void __init ptlock_cache_init(void)
{
- page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
+ page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(struct pt_lock), 0,
SLAB_PANIC, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
{
- spinlock_t *ptl;
+ struct pt_lock *pt_lock;
- ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
- if (!ptl)
+ pt_lock = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
+ if (!pt_lock)
return false;
- ptdesc->ptl = ptl;
+ ptdesc->ptl = pt_lock;
return true;
}
+static void ptlock_free_rcu(struct rcu_head *head)
+{
+ struct pt_lock *pt_lock;
+
+ pt_lock = container_of(head, struct pt_lock, rcu);
+ kmem_cache_free(page_ptl_cachep, pt_lock);
+}
+
void ptlock_free(struct ptdesc *ptdesc)
{
- kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
+ struct pt_lock *pt_lock = ptdesc->ptl;
+
+ call_rcu(&pt_lock->rcu, ptlock_free_rcu);
}
#endif
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index bc9a66ec6a6e4..4527c385935be 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1185,8 +1185,8 @@ static int move_pages_pte(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd,
}
/* Sanity checks before the operation */
- if (WARN_ON_ONCE(pmd_none(*dst_pmd)) || WARN_ON_ONCE(pmd_none(*src_pmd)) ||
- WARN_ON_ONCE(pmd_trans_huge(*dst_pmd)) || WARN_ON_ONCE(pmd_trans_huge(*src_pmd))) {
+ if (pmd_none(*dst_pmd) || pmd_none(*src_pmd) ||
+ pmd_trans_huge(*dst_pmd) || pmd_trans_huge(*src_pmd)) {
err = -EINVAL;
goto out;
}
--
2.20.1
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte
2024-12-09 9:31 ` Qi Zheng
@ 2024-12-09 11:39 ` syzbot
0 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2024-12-09 11:39 UTC (permalink / raw)
To: akpm, bp, dave.hansen, hpa, linux-kernel, linux-mm, mingo,
syzkaller-bugs, tglx, x86, zhengqi.arch
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
Tested-by: syzbot+1c58afed1cfd2f57efee@syzkaller.appspotmail.com
Tested on:
commit: 6e165f54 mm/page_isolation: fixup isolate_single_pageb..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
console output: https://syzkaller.appspot.com/x/log.txt?x=1760a3e8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=3884fb5fa6f2533c
dashboard link: https://syzkaller.appspot.com/bug?extid=1c58afed1cfd2f57efee
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=15aa5944580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2024-12-09 11:39 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-12-07 17:14 [syzbot] [mm?] KASAN: slab-use-after-free Read in move_pages_pte syzbot
2024-12-09 6:25 ` Qi Zheng
2024-12-09 6:48 ` Qi Zheng
2024-12-09 6:50 ` syzbot
2024-12-09 7:00 ` Qi Zheng
2024-12-09 7:02 ` syzbot
2024-12-09 7:56 ` Yu Zhao
2024-12-09 8:09 ` Qi Zheng
2024-12-09 9:20 ` Qi Zheng
2024-12-09 7:33 ` Qi Zheng
2024-12-09 7:51 ` syzbot
2024-12-09 7:58 ` Qi Zheng
2024-12-09 9:31 ` Qi Zheng
2024-12-09 11:39 ` syzbot
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