* [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf
@ 2026-02-09 18:26 syzbot
2026-03-02 3:41 ` Qing Wang
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2026-02-09 18:26 UTC (permalink / raw)
To: Liam.Howlett, akpm, chao, jaegeuk, jannh, linkinjeon,
linux-f2fs-devel, linux-fsdevel, linux-kernel, linux-mm,
lorenzo.stoakes, pfalcato, sj1557.seo, syzkaller-bugs, vbabka
Hello,
syzbot found the following issue on:
HEAD commit: e7aa57247700 Merge tag 'spi-fix-v6.19-rc8' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122ae7fa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9d7d0fbecb37bff8
dashboard link: https://syzkaller.appspot.com/bug?extid=cae7809e9dc1459e4e63
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=130e2944580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/28d29c9b5ae2/disk-e7aa5724.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0683244c7a0f/vmlinux-e7aa5724.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cd8cc5cb8b94/bzImage-e7aa5724.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f78f58e821b0/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10f7165a580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cae7809e9dc1459e4e63@syzkaller.appspotmail.com
BUG: memory leak
unreferenced object 0xffff888113218600 (size 512):
comm "sed", pid 6046, jiffies 4294945902
hex dump (first 32 bytes):
00 8e 13 29 81 88 ff ff 00 12 86 27 81 88 ff ff ...).......'....
00 5a 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 .Z..............
backtrace (crc 49909e19):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x465/0x680 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
alloc_empty_sheaf+0x36/0x50 mm/slub.c:2618
__kfree_rcu_sheaf+0x155/0x210 mm/slub.c:6304
kfree_rcu_sheaf mm/slab_common.c:1631 [inline]
kvfree_call_rcu+0x202/0x3d0 mm/slab_common.c:1981
ma_free_rcu lib/maple_tree.c:208 [inline]
ma_free_rcu+0x29/0x40 lib/maple_tree.c:205
mas_free lib/maple_tree.c:1174 [inline]
mas_replace_node lib/maple_tree.c:1581 [inline]
mas_wr_node_store+0x5fc/0x730 lib/maple_tree.c:3553
mas_wr_store_entry+0x4eb/0x760 lib/maple_tree.c:3764
mas_store_prealloc+0x358/0x740 lib/maple_tree.c:5169
vma_iter_store_overwrite mm/vma.h:544 [inline]
commit_merge+0x28e/0x490 mm/vma.c:763
vma_expand+0x264/0x460 mm/vma.c:1200
vma_merge_new_range+0xe3/0x350 mm/vma.c:1099
__mmap_region+0x54b/0x15b0 mm/vma.c:2747
mmap_region+0xfb/0x1e0 mm/vma.c:2830
do_mmap+0x7ac/0xb80 mm/mmap.c:558
vm_mmap_pgoff+0x1a6/0x2d0 mm/util.c:581
ksys_mmap_pgoff+0x233/0x2d0 mm/mmap.c:604
BUG: memory leak
unreferenced object 0xffff888127861200 (size 512):
comm "udevd", pid 6236, jiffies 4294948784
hex dump (first 32 bytes):
00 86 21 13 81 88 ff ff 18 e0 05 00 81 88 ff ff ..!.............
00 5a 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 .Z..............
backtrace (crc 5b72581e):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x465/0x680 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
alloc_empty_sheaf+0x36/0x50 mm/slub.c:2618
__kfree_rcu_sheaf+0x155/0x210 mm/slub.c:6304
kfree_rcu_sheaf mm/slab_common.c:1631 [inline]
kvfree_call_rcu+0x202/0x3d0 mm/slab_common.c:1981
ma_free_rcu lib/maple_tree.c:208 [inline]
ma_free_rcu+0x29/0x40 lib/maple_tree.c:205
mas_topiary_node lib/maple_tree.c:2311 [inline]
mas_topiary_node lib/maple_tree.c:2299 [inline]
mas_topiary_replace+0xb0f/0x1400 lib/maple_tree.c:2410
mas_wmb_replace lib/maple_tree.c:2433 [inline]
mas_spanning_rebalance+0x14e1/0x24b0 lib/maple_tree.c:2738
mas_wr_spanning_store+0x983/0x10d0 lib/maple_tree.c:3479
mas_wr_store_entry+0x4d5/0x760 lib/maple_tree.c:3767
mas_store_gfp+0x341/0x640 lib/maple_tree.c:5138
vma_iter_clear_gfp include/linux/mm.h:1141 [inline]
do_vmi_align_munmap+0x259/0x2d0 mm/vma.c:1574
do_vmi_munmap+0x17c/0x280 mm/vma.c:1627
__vm_munmap+0xec/0x200 mm/vma.c:3247
__do_sys_munmap mm/mmap.c:1077 [inline]
__se_sys_munmap mm/mmap.c:1074 [inline]
__x64_sys_munmap+0x1f/0x30 mm/mmap.c:1074
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff88812c458000 (size 4480):
comm "udevd", pid 5181, jiffies 4294950983
hex dump (first 32 bytes):
01 00 08 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 80 00 00 00 00 00 00 00 ................
backtrace (crc ad4af9e6):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_node_noprof+0x422/0x590 mm/slub.c:5315
alloc_task_struct_node kernel/fork.c:184 [inline]
dup_task_struct kernel/fork.c:915 [inline]
copy_process+0x286/0x2870 kernel/fork.c:2052
kernel_clone+0xac/0x6e0 kernel/fork.c:2651
__do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff8881274a1540 (size 184):
comm "udevd", pid 5181, jiffies 4294950983
hex dump (first 32 bytes):
02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 54e589bc):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x412/0x580 mm/slub.c:5270
prepare_creds+0x22/0x600 kernel/cred.c:185
copy_creds+0x44/0x290 kernel/cred.c:286
copy_process+0x7a7/0x2870 kernel/fork.c:2086
kernel_clone+0xac/0x6e0 kernel/fork.c:2651
__do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff888109639020 (size 32):
comm "udevd", pid 5181, jiffies 4294950983
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f8 52 86 00 81 88 ff ff 00 00 00 00 00 00 00 00 .R..............
backtrace (crc 336e1c5f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x465/0x680 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
lsm_blob_alloc+0x4d/0x80 security/security.c:192
lsm_cred_alloc security/security.c:209 [inline]
security_prepare_creds+0x2d/0x290 security/security.c:2763
prepare_creds+0x395/0x600 kernel/cred.c:215
copy_creds+0x44/0x290 kernel/cred.c:286
copy_process+0x7a7/0x2870 kernel/fork.c:2086
kernel_clone+0xac/0x6e0 kernel/fork.c:2651
__do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff888126fdbd80 (size 64):
comm "udevd", pid 5181, jiffies 4294950983
hex dump (first 32 bytes):
c0 c3 4e 46 81 88 ff ff 00 00 00 00 00 00 00 00 ..NF............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 508a43e4):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x465/0x680 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
lsm_blob_alloc+0x4d/0x80 security/security.c:192
lsm_task_alloc security/security.c:244 [inline]
security_task_alloc+0x2a/0x260 security/security.c:2682
copy_process+0xf07/0x2870 kernel/fork.c:2203
kernel_clone+0xac/0x6e0 kernel/fork.c:2651
__do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF
---
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.
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] 4+ messages in thread* Re: [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf
2026-02-09 18:26 [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf syzbot
@ 2026-03-02 3:41 ` Qing Wang
2026-03-02 3:57 ` syzbot
2026-03-02 8:39 ` Vlastimil Babka (SUSE)
0 siblings, 2 replies; 4+ messages in thread
From: Qing Wang @ 2026-03-02 3:41 UTC (permalink / raw)
To: syzbot+cae7809e9dc1459e4e63
Cc: Liam.Howlett, akpm, chao, jaegeuk, jannh, linkinjeon,
linux-f2fs-devel, linux-fsdevel, linux-kernel, linux-mm,
lorenzo.stoakes, pfalcato, sj1557.seo, syzkaller-bugs, vbabka
#syz test
diff --git a/mm/slub.c b/mm/slub.c
index cdc1e652ec52..387979b89120 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -6307,15 +6307,21 @@ bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj)
goto fail;
if (!local_trylock(&s->cpu_sheaves->lock)) {
- barn_put_empty_sheaf(barn, empty);
+ if (barn && data_race(barn->nr_empty) < MAX_EMPTY_SHEAVES)
+ barn_put_empty_sheaf(barn, empty);
+ else
+ free_empty_sheaf(s, empty);
goto fail;
}
pcs = this_cpu_ptr(s->cpu_sheaves);
- if (unlikely(pcs->rcu_free))
- barn_put_empty_sheaf(barn, empty);
- else
+ if (unlikely(pcs->rcu_free)) {
+ if (barn && data_race(barn->nr_empty) < MAX_EMPTY_SHEAVES)
+ barn_put_empty_sheaf(barn, empty);
+ else
+ free_empty_sheaf(s, empty);
+ } else
pcs->rcu_free = empty;
}
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf
2026-03-02 3:41 ` Qing Wang
@ 2026-03-02 3:57 ` syzbot
2026-03-02 8:39 ` Vlastimil Babka (SUSE)
1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2026-03-02 3:57 UTC (permalink / raw)
To: akpm, chao, jaegeuk, jannh, liam.howlett, linkinjeon,
linux-f2fs-devel, linux-fsdevel, linux-kernel, linux-mm,
lorenzo.stoakes, pfalcato, sj1557.seo, syzkaller-bugs, vbabka,
wangqing7171
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
memory leak in __pcs_replace_empty_main
BUG: memory leak
unreferenced object 0xffff88810005fa00 (size 512):
comm "swapper/0", pid 0, jiffies 4294937296
hex dump (first 32 bytes):
00 2e c5 05 81 88 ff ff 00 a2 96 0a 81 88 ff ff ................
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc ee49fed0):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x1e4/0x260 mm/slub.c:4602
alloc_from_pcs mm/slub.c:4695 [inline]
slab_alloc_node mm/slub.c:4829 [inline]
__kmalloc_cache_noprof+0x3ac/0x480 mm/slub.c:5353
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__irq_domain_alloc_fwnode+0x37/0x140 kernel/irq/irqdomain.c:95
irq_domain_alloc_named_fwnode include/linux/irqdomain.h:271 [inline]
arch_early_irq_init+0x1c/0x70 arch/x86/kernel/apic/vector.c:803
start_kernel+0x931/0xb80 init/main.c:1114
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0xce/0xd0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
BUG: memory leak
unreferenced object 0xffff8881008f8c00 (size 512):
comm "kthreadd", pid 2, jiffies 4294937339
hex dump (first 32 bytes):
00 d6 04 00 81 88 ff ff 00 92 96 0a 81 88 ff ff ................
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc f2ef5290):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x1e4/0x260 mm/slub.c:4602
alloc_from_pcs mm/slub.c:4695 [inline]
slab_alloc_node mm/slub.c:4829 [inline]
__kmalloc_cache_node_noprof+0x3ef/0x4e0 mm/slub.c:5366
kmalloc_node_noprof include/linux/slab.h:1077 [inline]
__get_vm_area_node+0xc6/0x1d0 mm/vmalloc.c:3221
__vmalloc_node_range_noprof+0x1d3/0xe50 mm/vmalloc.c:4024
__vmalloc_node_noprof+0x71/0x90 mm/vmalloc.c:4124
alloc_thread_stack_node kernel/fork.c:355 [inline]
dup_task_struct kernel/fork.c:924 [inline]
copy_process+0x3e5/0x28c0 kernel/fork.c:2050
kernel_clone+0xac/0x6e0 kernel/fork.c:2654
kernel_thread+0x80/0xb0 kernel/fork.c:2715
create_kthread kernel/kthread.c:490 [inline]
kthreadd+0x186/0x250 kernel/kthread.c:848
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff888105c53200 (size 512):
comm "kworker/1:0", pid 23, jiffies 4294937917
hex dump (first 32 bytes):
00 a2 96 0a 81 88 ff ff 00 d4 04 00 81 88 ff ff ................
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc d24dd055):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe9/0x2c0 mm/slub.c:5700
free_to_pcs mm/slub.c:5753 [inline]
slab_free mm/slub.c:6154 [inline]
kfree+0x352/0x390 mm/slub.c:6467
vfree.part.0+0x1d5/0x4d0 mm/vmalloc.c:3485
vfree mm/vmalloc.c:3456 [inline]
delayed_vfree_work+0x5b/0x90 mm/vmalloc.c:3398
process_one_work+0x26c/0x5d0 kernel/workqueue.c:3275
process_scheduled_works kernel/workqueue.c:3358 [inline]
worker_thread+0x243/0x490 kernel/workqueue.c:3439
kthread+0x14e/0x1a0 kernel/kthread.c:467
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff888105c52e00 (size 512):
comm "kworker/u8:5", pid 4440, jiffies 4294937918
hex dump (first 32 bytes):
c8 2c 04 00 81 88 ff ff 00 fa 05 00 81 88 ff ff .,..............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc a68b63de):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe9/0x2c0 mm/slub.c:5700
free_to_pcs mm/slub.c:5753 [inline]
slab_free mm/slub.c:6154 [inline]
kfree+0x352/0x390 mm/slub.c:6467
call_usermodehelper_freeinfo kernel/umh.c:43 [inline]
umh_complete kernel/umh.c:57 [inline]
call_usermodehelper_exec_async+0x1c7/0x1f0 kernel/umh.c:119
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
BUG: memory leak
unreferenced object 0xffff88810a96a200 (size 512):
comm "udevadm", pid 5177, jiffies 4294938175
hex dump (first 32 bytes):
00 fa 05 00 81 88 ff ff 00 32 c5 05 81 88 ff ff .........2......
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 94107438):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x1e4/0x260 mm/slub.c:4602
alloc_from_pcs mm/slub.c:4695 [inline]
slab_alloc_node mm/slub.c:4829 [inline]
__kmalloc_cache_noprof+0x3ac/0x480 mm/slub.c:5353
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
kernfs_get_open_node fs/kernfs/file.c:543 [inline]
kernfs_fop_open+0x4f3/0x580 fs/kernfs/file.c:718
do_dentry_open+0x202/0x8d0 fs/open.c:949
vfs_open+0x3d/0x1b0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x154d/0x1e20 fs/namei.c:4830
do_file_open+0x121/0x200 fs/namei.c:4859
do_sys_openat2+0xa5/0x140 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x82/0xf0 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BUG: memory leak
unreferenced object 0xffff888109d58400 (size 512):
comm "udevd", pid 5176, jiffies 4294938222
hex dump (first 32 bytes):
00 12 47 2a 81 88 ff ff 00 ee 46 2a 81 88 ff ff ..G*......F*....
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc af8b5cec):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4520 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
__do_kmalloc_node mm/slub.c:5237 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5250
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__kfree_rcu_sheaf+0x164/0x240 mm/slub.c:5887
kfree_rcu_sheaf mm/slab_common.c:1608 [inline]
kvfree_call_rcu+0x1f6/0x3c0 mm/slab_common.c:1957
kernfs_unlink_open_file+0x194/0x1b0 fs/kernfs/file.c:604
kernfs_fop_release+0x55/0x110 fs/kernfs/file.c:783
__fput+0x1b5/0x4f0 fs/file_table.c:469
fput_close_sync+0x67/0x120 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x4a/0xc0 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF
Tested on:
commit: 11439c46 Linux 7.0-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1277a202580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2c6ad6fefffa76b1
dashboard link: https://syzkaller.appspot.com/bug?extid=cae7809e9dc1459e4e63
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=13801006580000
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf
2026-03-02 3:41 ` Qing Wang
2026-03-02 3:57 ` syzbot
@ 2026-03-02 8:39 ` Vlastimil Babka (SUSE)
1 sibling, 0 replies; 4+ messages in thread
From: Vlastimil Babka (SUSE) @ 2026-03-02 8:39 UTC (permalink / raw)
To: Qing Wang, syzbot+cae7809e9dc1459e4e63
Cc: Liam.Howlett, akpm, chao, jaegeuk, jannh, linkinjeon,
linux-f2fs-devel, linux-fsdevel, linux-kernel, linux-mm,
lorenzo.stoakes, pfalcato, sj1557.seo, syzkaller-bugs, vbabka,
Harry Yoo, Hao Li
On 3/2/26 04:41, Qing Wang wrote:
> #syz test
>
> diff --git a/mm/slub.c b/mm/slub.c
> index cdc1e652ec52..387979b89120 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -6307,15 +6307,21 @@ bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj)
> goto fail;
>
> if (!local_trylock(&s->cpu_sheaves->lock)) {
> - barn_put_empty_sheaf(barn, empty);
> + if (barn && data_race(barn->nr_empty) < MAX_EMPTY_SHEAVES)
> + barn_put_empty_sheaf(barn, empty);
> + else
> + free_empty_sheaf(s, empty);
> goto fail;
> }
>
> pcs = this_cpu_ptr(s->cpu_sheaves);
>
> - if (unlikely(pcs->rcu_free))
> - barn_put_empty_sheaf(barn, empty);
> - else
> + if (unlikely(pcs->rcu_free)) {
> + if (barn && data_race(barn->nr_empty) < MAX_EMPTY_SHEAVES)
> + barn_put_empty_sheaf(barn, empty);
> + else
> + free_empty_sheaf(s, empty);
> + } else
> pcs->rcu_free = empty;
> }
I don't think this would fix any leak, and syzbot agrees. It would limit the
empty sheaves in barn more strictly, but they are not leaked.
Hm I don't see any leak in __kfree_rcu_sheaf() or rcu_free_sheaf(). Wonder
if kmemleak lacks visibility into barns or pcs's as roots for searching what
objects are considered referenced, or something?
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-03-02 8:39 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-02-09 18:26 [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf syzbot
2026-03-02 3:41 ` Qing Wang
2026-03-02 3:57 ` syzbot
2026-03-02 8:39 ` Vlastimil Babka (SUSE)
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox