* [syzbot] [mm?] general protection fault in shmem_mapping
@ 2025-02-14 15:48 syzbot
2025-02-14 18:57 ` Zi Yan
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: syzbot @ 2025-02-14 15:48 UTC (permalink / raw)
To: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs, ziy
Hello,
syzbot found the following issue on:
HEAD commit: df5d6180169a Add linux-next specific files for 20250210
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7
dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9
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=138972a4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz
The issue was bisected to:
commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40
Author: Zi Yan <ziy@nvidia.com>
Date: Wed Feb 5 03:14:13 2025 +0000
mm/huge_memory: add buddy allocator like folio_split()
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000
console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com
Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()")
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127]
CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281
Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48
RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006
RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000
RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008
R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018
R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000
FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587
__folio_split+0x1267/0x16d0 mm/huge_memory.c:3871
try_folio_split include/linux/huge_mm.h:374 [inline]
truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230
shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144
shmem_truncate_range mm/shmem.c:1224 [inline]
shmem_fallocate+0x431/0xf20 mm/shmem.c:3674
vfs_fallocate+0x623/0x7a0 fs/open.c:338
madvise_remove mm/madvise.c:1034 [inline]
madvise_vma_behavior mm/madvise.c:1269 [inline]
madvise_walk_vmas mm/madvise.c:1511 [inline]
madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646
do_madvise mm/madvise.c:1744 [inline]
__do_sys_madvise mm/madvise.c:1752 [inline]
__se_sys_madvise mm/madvise.c:1750 [inline]
__x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750
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: 0033:0x7f5e04576519
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519
RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000
RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074
R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281
Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48
RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006
RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000
RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008
R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018
R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000
FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: f3 0f 1e fa endbr64
9: 53 push %rbx
a: 48 89 fb mov %rdi,%rbx
d: e8 c3 3a bd ff call 0xffbd3ad5
12: 48 81 c3 20 01 00 00 add $0x120,%rbx
19: 48 89 d8 mov %rbx,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 48 89 df mov %rbx,%rdi
33: e8 dd 35 24 00 call 0x243615
38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax
3f: 48 rex.W
---
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:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 15:48 [syzbot] [mm?] general protection fault in shmem_mapping syzbot @ 2025-02-14 18:57 ` Zi Yan 2025-02-14 23:26 ` Zi Yan 2025-02-15 0:48 ` Zi Yan 2 siblings, 0 replies; 8+ messages in thread From: Zi Yan @ 2025-02-14 18:57 UTC (permalink / raw) To: syzbot; +Cc: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs On 14 Feb 2025, at 10:48, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: df5d6180169a Add linux-next specific files for 20250210 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 > dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 > 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=138972a4580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz > kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz > > The issue was bisected to: > > commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 > Author: Zi Yan <ziy@nvidia.com> > Date: Wed Feb 5 03:14:13 2025 +0000 > > mm/huge_memory: add buddy allocator like folio_split() > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 > console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 I have reproduced it locally and am working on a fix. Thanks for the reporting. Best Regards, Yan, Zi ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 15:48 [syzbot] [mm?] general protection fault in shmem_mapping syzbot 2025-02-14 18:57 ` Zi Yan @ 2025-02-14 23:26 ` Zi Yan 2025-02-14 23:26 ` syzbot 2025-02-15 0:48 ` Zi Yan 2 siblings, 1 reply; 8+ messages in thread From: Zi Yan @ 2025-02-14 23:26 UTC (permalink / raw) To: syzbot; +Cc: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs On 14 Feb 2025, at 10:48, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: df5d6180169a Add linux-next specific files for 20250210 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 > dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 > 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=138972a4580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz > kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz > > The issue was bisected to: > > commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 > Author: Zi Yan <ziy@nvidia.com> > Date: Wed Feb 5 03:14:13 2025 +0000 > > mm/huge_memory: add buddy allocator like folio_split() > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 > console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com > Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()") > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] > CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 > RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 > Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 > RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 > RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 > RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 > RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 > R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 > R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 > FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587 > __folio_split+0x1267/0x16d0 mm/huge_memory.c:3871 > try_folio_split include/linux/huge_mm.h:374 [inline] > truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230 > shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144 > shmem_truncate_range mm/shmem.c:1224 [inline] > shmem_fallocate+0x431/0xf20 mm/shmem.c:3674 > vfs_fallocate+0x623/0x7a0 fs/open.c:338 > madvise_remove mm/madvise.c:1034 [inline] > madvise_vma_behavior mm/madvise.c:1269 [inline] > madvise_walk_vmas mm/madvise.c:1511 [inline] > madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646 > do_madvise mm/madvise.c:1744 [inline] > __do_sys_madvise mm/madvise.c:1752 [inline] > __se_sys_madvise mm/madvise.c:1750 [inline] > __x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750 > 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: 0033:0x7f5e04576519 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519 > RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000 > RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074 > R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 > Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 > RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 > RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 > RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 > RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 > R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 > R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 > FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 90 nop > 1: 90 nop > 2: 90 nop > 3: 90 nop > 4: 90 nop > 5: f3 0f 1e fa endbr64 > 9: 53 push %rbx > a: 48 89 fb mov %rdi,%rbx > d: e8 c3 3a bd ff call 0xffbd3ad5 > 12: 48 81 c3 20 01 00 00 add $0x120,%rbx > 19: 48 89 d8 mov %rbx,%rax > 1c: 48 c1 e8 03 shr $0x3,%rax > 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx > 27: fc ff df > * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction > 2e: 74 08 je 0x38 > 30: 48 89 df mov %rbx,%rdi > 33: e8 dd 35 24 00 call 0x243615 > 38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax > 3f: 48 rex.W > #syz test: github.com:x-y-z/linux-1gb-thp.git syzkaller_fix_20250114 origin_folio->mapping becomes NULL, since it was dropped, and the remaining after-split folios are still trying to use origin_folio->mapping. It leads to the error. And the original __split_huge_page() did not check origin_folio->index nor dropped it. __split_unmapped_folio() should keep the original behavior. Fixed it by not dropping origin_folio. My local test do not fail and I am triggering syzbot to test the change to confirm it. Best Regards, Yan, Zi ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 23:26 ` Zi Yan @ 2025-02-14 23:26 ` syzbot 2025-02-14 23:28 ` Zi Yan 0 siblings, 1 reply; 8+ messages in thread From: syzbot @ 2025-02-14 23:26 UTC (permalink / raw) To: ziy; +Cc: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs, ziy > On 14 Feb 2025, at 10:48, syzbot wrote: > >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: df5d6180169a Add linux-next specific files for 20250210 >> git tree: linux-next >> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 >> dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 >> 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=138972a4580000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz >> >> The issue was bisected to: >> >> commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 >> Author: Zi Yan <ziy@nvidia.com> >> Date: Wed Feb 5 03:14:13 2025 +0000 >> >> mm/huge_memory: add buddy allocator like folio_split() >> >> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 >> final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 >> console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com >> Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()") >> >> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI >> KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] >> CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 >> RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 >> Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 >> RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 >> RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 >> RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 >> RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 >> R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 >> R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 >> FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> <TASK> >> __split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587 >> __folio_split+0x1267/0x16d0 mm/huge_memory.c:3871 >> try_folio_split include/linux/huge_mm.h:374 [inline] >> truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230 >> shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144 >> shmem_truncate_range mm/shmem.c:1224 [inline] >> shmem_fallocate+0x431/0xf20 mm/shmem.c:3674 >> vfs_fallocate+0x623/0x7a0 fs/open.c:338 >> madvise_remove mm/madvise.c:1034 [inline] >> madvise_vma_behavior mm/madvise.c:1269 [inline] >> madvise_walk_vmas mm/madvise.c:1511 [inline] >> madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646 >> do_madvise mm/madvise.c:1744 [inline] >> __do_sys_madvise mm/madvise.c:1752 [inline] >> __se_sys_madvise mm/madvise.c:1750 [inline] >> __x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750 >> 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: 0033:0x7f5e04576519 >> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c >> RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519 >> RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000 >> RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074 >> R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040 >> </TASK> >> Modules linked in: >> ---[ end trace 0000000000000000 ]--- >> RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 >> Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 >> RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 >> RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 >> RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 >> RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 >> R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 >> R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 >> FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> ---------------- >> Code disassembly (best guess): >> 0: 90 nop >> 1: 90 nop >> 2: 90 nop >> 3: 90 nop >> 4: 90 nop >> 5: f3 0f 1e fa endbr64 >> 9: 53 push %rbx >> a: 48 89 fb mov %rdi,%rbx >> d: e8 c3 3a bd ff call 0xffbd3ad5 >> 12: 48 81 c3 20 01 00 00 add $0x120,%rbx >> 19: 48 89 d8 mov %rbx,%rax >> 1c: 48 c1 e8 03 shr $0x3,%rax >> 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx >> 27: fc ff df >> * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction >> 2e: 74 08 je 0x38 >> 30: 48 89 df mov %rbx,%rdi >> 33: e8 dd 35 24 00 call 0x243615 >> 38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax >> 3f: 48 rex.W >> > > > #syz test: github.com:x-y-z/linux-1gb-thp.git syzkaller_fix_20250114 "github.com:x-y-z/linux-1gb-thp.git" does not look like a valid git repo address. > > origin_folio->mapping becomes NULL, since it was dropped, and the remaining > after-split folios are still trying to use origin_folio->mapping. It leads > to the error. And the original __split_huge_page() did not check > origin_folio->index nor dropped it. __split_unmapped_folio() should keep > the original behavior. > > Fixed it by not dropping origin_folio. > > My local test do not fail and I am triggering syzbot to test the change > to confirm it. > > Best Regards, > Yan, Zi ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 23:26 ` syzbot @ 2025-02-14 23:28 ` Zi Yan 2025-02-14 23:45 ` syzbot 0 siblings, 1 reply; 8+ messages in thread From: Zi Yan @ 2025-02-14 23:28 UTC (permalink / raw) To: syzbot; +Cc: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs On 14 Feb 2025, at 18:26, syzbot wrote: >> On 14 Feb 2025, at 10:48, syzbot wrote: >> >>> Hello, >>> >>> syzbot found the following issue on: >>> >>> HEAD commit: df5d6180169a Add linux-next specific files for 20250210 >>> git tree: linux-next >>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 >>> dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 >>> 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=138972a4580000 >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 >>> >>> Downloadable assets: >>> disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz >>> vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz >>> kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz >>> >>> The issue was bisected to: >>> >>> commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 >>> Author: Zi Yan <ziy@nvidia.com> >>> Date: Wed Feb 5 03:14:13 2025 +0000 >>> >>> mm/huge_memory: add buddy allocator like folio_split() >>> >>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 >>> final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 >>> console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 >>> >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>> Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com >>> Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()") >>> >>> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI >>> KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] >>> CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0 >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 >>> RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 >>> Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 >>> RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 >>> RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 >>> RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 >>> RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 >>> R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 >>> R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 >>> FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> Call Trace: >>> <TASK> >>> __split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587 >>> __folio_split+0x1267/0x16d0 mm/huge_memory.c:3871 >>> try_folio_split include/linux/huge_mm.h:374 [inline] >>> truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230 >>> shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144 >>> shmem_truncate_range mm/shmem.c:1224 [inline] >>> shmem_fallocate+0x431/0xf20 mm/shmem.c:3674 >>> vfs_fallocate+0x623/0x7a0 fs/open.c:338 >>> madvise_remove mm/madvise.c:1034 [inline] >>> madvise_vma_behavior mm/madvise.c:1269 [inline] >>> madvise_walk_vmas mm/madvise.c:1511 [inline] >>> madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646 >>> do_madvise mm/madvise.c:1744 [inline] >>> __do_sys_madvise mm/madvise.c:1752 [inline] >>> __se_sys_madvise mm/madvise.c:1750 [inline] >>> __x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750 >>> 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: 0033:0x7f5e04576519 >>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c >>> RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519 >>> RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000 >>> RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000 >>> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074 >>> R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040 >>> </TASK> >>> Modules linked in: >>> ---[ end trace 0000000000000000 ]--- >>> RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 >>> Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 >>> RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 >>> RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 >>> RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 >>> RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 >>> R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 >>> R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 >>> FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> ---------------- >>> Code disassembly (best guess): >>> 0: 90 nop >>> 1: 90 nop >>> 2: 90 nop >>> 3: 90 nop >>> 4: 90 nop >>> 5: f3 0f 1e fa endbr64 >>> 9: 53 push %rbx >>> a: 48 89 fb mov %rdi,%rbx >>> d: e8 c3 3a bd ff call 0xffbd3ad5 >>> 12: 48 81 c3 20 01 00 00 add $0x120,%rbx >>> 19: 48 89 d8 mov %rbx,%rax >>> 1c: 48 c1 e8 03 shr $0x3,%rax >>> 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx >>> 27: fc ff df >>> * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction >>> 2e: 74 08 je 0x38 >>> 30: 48 89 df mov %rbx,%rdi >>> 33: e8 dd 35 24 00 call 0x243615 >>> 38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax >>> 3f: 48 rex.W >>> >> >> >> #syz test: github.com:x-y-z/linux-1gb-thp.git syzkaller_fix_20250114 > > "github.com:x-y-z/linux-1gb-thp.git" does not look like a valid git repo address. #syz test: git@github.com:x-y-z/linux-1gb-thp.git syzkaller_fix_20250114 Best Regards, Yan, Zi ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 23:28 ` Zi Yan @ 2025-02-14 23:45 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2025-02-14 23:45 UTC (permalink / raw) To: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs, ziy Hello, syzbot tried to test the proposed patch but the build/boot failed: failed to checkout kernel repo git@github.com:x-y-z/linux-1gb-thp.git/syzkaller_fix_20250114: failed to run ["git" "fetch" "--force" "21c4e043f63ee530c32221be8efae42773de1c65" "syzkaller_fix_20250114"]: exit status 128 Host key verification failed. fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists. Tested on: commit: [unknown git tree: git@github.com:x-y-z/linux-1gb-thp.git syzkaller_fix_20250114 kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 compiler: Note: no patches were applied. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-14 15:48 [syzbot] [mm?] general protection fault in shmem_mapping syzbot 2025-02-14 18:57 ` Zi Yan 2025-02-14 23:26 ` Zi Yan @ 2025-02-15 0:48 ` Zi Yan 2025-02-15 1:15 ` syzbot 2 siblings, 1 reply; 8+ messages in thread From: Zi Yan @ 2025-02-15 0:48 UTC (permalink / raw) To: syzbot; +Cc: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs [-- Attachment #1: Type: text/plain, Size: 7190 bytes --] On 14 Feb 2025, at 10:48, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: df5d6180169a Add linux-next specific files for 20250210 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=16d343f8580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 > dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 > 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=138972a4580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11737b18580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/92495cf20271/disk-df5d6180.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/4b3656161842/vmlinux-df5d6180.xz > kernel image: https://storage.googleapis.com/syzbot-assets/7fbc4e7a0f5d/bzImage-df5d6180.xz > > The issue was bisected to: > > commit 19c067c8a0f18b62d4a4235b0b327624c86f2e40 > Author: Zi Yan <ziy@nvidia.com> > Date: Wed Feb 5 03:14:13 2025 +0000 > > mm/huge_memory: add buddy allocator like folio_split() > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102f9bdf980000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=122f9bdf980000 > console output: https://syzkaller.appspot.com/x/log.txt?x=142f9bdf980000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com > Fixes: 19c067c8a0f1 ("mm/huge_memory: add buddy allocator like folio_split()") > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] > CPU: 1 UID: 0 PID: 5949 Comm: syz-executor163 Not tainted 6.14.0-rc2-next-20250210-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 > RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 > Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 > RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 > RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 > RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 > RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 > R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 > R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 > FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __split_unmapped_folio+0x238a/0x3e50 mm/huge_memory.c:3587 > __folio_split+0x1267/0x16d0 mm/huge_memory.c:3871 > try_folio_split include/linux/huge_mm.h:374 [inline] > truncate_inode_partial_folio+0x55d/0xdc0 mm/truncate.c:230 > shmem_undo_range+0xab7/0x1820 mm/shmem.c:1144 > shmem_truncate_range mm/shmem.c:1224 [inline] > shmem_fallocate+0x431/0xf20 mm/shmem.c:3674 > vfs_fallocate+0x623/0x7a0 fs/open.c:338 > madvise_remove mm/madvise.c:1034 [inline] > madvise_vma_behavior mm/madvise.c:1269 [inline] > madvise_walk_vmas mm/madvise.c:1511 [inline] > madvise_do_behavior+0x1f29/0x3c00 mm/madvise.c:1646 > do_madvise mm/madvise.c:1744 [inline] > __do_sys_madvise mm/madvise.c:1752 [inline] > __se_sys_madvise mm/madvise.c:1750 [inline] > __x64_sys_madvise+0x11b/0x140 mm/madvise.c:1750 > 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: 0033:0x7f5e04576519 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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:00007f5e04531218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 00007f5e04600308 RCX: 00007f5e04576519 > RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000400000000000 > RBP: 00007f5e04600300 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e045cd074 > R13: 0000400000000000 R14: 0000400000000140 R15: 0000400000000040 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:shmem_mapping+0x25/0x50 mm/shmem.c:281 > Code: 90 90 90 90 90 f3 0f 1e fa 53 48 89 fb e8 c3 3a bd ff 48 81 c3 20 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 dd 35 24 00 48 c7 c0 80 6c 14 8c 48 > RSP: 0018:ffffc90004036dd8 EFLAGS: 00010006 > RAX: 0000000000000024 RBX: 0000000000000120 RCX: dffffc0000000000 > RDX: 0000000000000000 RSI: 0000000000000600 RDI: 0000000000000000 > RBP: 0000000000000600 R08: ffffffff822bcf18 R09: 1ffffd4000331008 > R10: dffffc0000000000 R11: fffff94000331009 R12: ffffea0001988018 > R13: ffffea0001988080 R14: ffffea0001988018 R15: ffffea0001988000 > FS: 00007f5e045316c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5e0458dae0 CR3: 0000000023c78000 CR4: 00000000003526f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 90 nop > 1: 90 nop > 2: 90 nop > 3: 90 nop > 4: 90 nop > 5: f3 0f 1e fa endbr64 > 9: 53 push %rbx > a: 48 89 fb mov %rdi,%rbx > d: e8 c3 3a bd ff call 0xffbd3ad5 > 12: 48 81 c3 20 01 00 00 add $0x120,%rbx > 19: 48 89 d8 mov %rbx,%rax > 1c: 48 c1 e8 03 shr $0x3,%rax > 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx > 27: fc ff df > * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction > 2e: 74 08 je 0x38 > 30: 48 89 df mov %rbx,%rdi > 33: e8 dd 35 24 00 call 0x243615 > 38: 48 c7 c0 80 6c 14 8c mov $0xffffffff8c146c80,%rax > 3f: 48 rex.W OK, I figured out how to trigger syzkaller to do the test. The attached patch includes both the fix and the __split_folio_to_order() change discussed at https://lore.kernel.org/linux-mm/d989ef66-4a4b-4679-b2e9-f05916ca3672@redhat.com/. I will paste the patch to my original patch email once syzkaller confirms it fixes the issue. #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git df5d6180169a Best Regards, Yan, Zi [-- Attachment #2: 0001-mm-huge_memory-do-not-drop-the-original-folio-during.patch --] [-- Type: text/plain, Size: 2764 bytes --] From a6bd83dfbb1143f1614ede4817cccb1e8cc6290d Mon Sep 17 00:00:00 2001 From: Zi Yan <ziy@nvidia.com> Date: Fri, 14 Feb 2025 16:18:24 -0500 Subject: [PATCH] mm/huge_memory: do not drop the original folio during truncate. The caller expects to handle the original folio itself. also make __split_unmapped_folio() never fail, per discussion with David Hildenbrand. Signed-off-by: Zi Yan <ziy@nvidia.com> --- mm/huge_memory.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2eda2a9ec8fc..87cb62c81bf3 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3292,16 +3292,12 @@ bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins) * It splits @folio into @new_order folios and copies the @folio metadata to * all the resulting folios. */ -static int __split_folio_to_order(struct folio *folio, int new_order) +static void __split_folio_to_order(struct folio *folio, int new_order) { - int curr_order = folio_order(folio); long nr_pages = folio_nr_pages(folio); long new_nr_pages = 1 << new_order; long index; - if (curr_order <= new_order) - return -EINVAL; - /* * Skip the first new_nr_pages, since the new folio from them have all * the flags from the original folio. @@ -3396,8 +3392,6 @@ static int __split_folio_to_order(struct folio *folio, int new_order) if (!new_order) ClearPageCompound(&folio->page); - - return 0; } /* @@ -3491,7 +3485,6 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, int old_order = folio_order(folio); struct folio *release; struct folio *end_folio = folio_next(folio); - int status; /* order-1 anonymous folio is not supported */ if (folio_test_anon(folio) && split_order == 1) @@ -3524,12 +3517,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, split_page_owner(&folio->page, old_order, split_order); pgalloc_tag_split(folio, old_order, split_order); - status = __split_folio_to_order(folio, split_order); - - if (status < 0) { - stop_split = true; - ret = -EINVAL; - } + __split_folio_to_order(folio, split_order); after_split: /* @@ -3567,8 +3555,10 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, folio_test_swapcache(origin_folio)) ? folio_nr_pages(release) : 0)); - if (release != origin_folio) - lru_add_page_tail(origin_folio, &release->page, + if (release == origin_folio) + continue; + + lru_add_page_tail(origin_folio, &release->page, lruvec, list); /* Some pages can be beyond EOF: drop them from page cache */ -- 2.47.2 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [mm?] general protection fault in shmem_mapping 2025-02-15 0:48 ` Zi Yan @ 2025-02-15 1:15 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2025-02-15 1:15 UTC (permalink / raw) To: akpm, hughd, linux-kernel, linux-mm, syzkaller-bugs, ziy Hello, syzbot has tested the proposed patch and the reproducer did not trigger any issue: Reported-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com Tested-by: syzbot+012c6245eaea0e23f7f9@syzkaller.appspotmail.com Tested on: commit: df5d6180 Add linux-next specific files for 20250210 git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git console output: https://syzkaller.appspot.com/x/log.txt?x=13bd19a4580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2cd616b6e736ca7 dashboard link: https://syzkaller.appspot.com/bug?extid=012c6245eaea0e23f7f9 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 patch: https://syzkaller.appspot.com/x/patch.diff?x=11a7a098580000 Note: testing is done by a robot and is best-effort only. ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2025-02-15 1:15 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2025-02-14 15:48 [syzbot] [mm?] general protection fault in shmem_mapping syzbot 2025-02-14 18:57 ` Zi Yan 2025-02-14 23:26 ` Zi Yan 2025-02-14 23:26 ` syzbot 2025-02-14 23:28 ` Zi Yan 2025-02-14 23:45 ` syzbot 2025-02-15 0:48 ` Zi Yan 2025-02-15 1:15 ` syzbot
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