[v6.6] KASAN: slab-use-after-free Read in f2fs_record_error_work

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c596736dadab Linux 6.6.120
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=109b599a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=691a6769a86ac817
dashboard link: https://syzkaller.appspot.com/bug?extid=bc2d4dea94357de41613
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/855c94eb3eef/disk-c596736d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b7510b30b774/vmlinux-c596736d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3ce7fe4f6991/bzImage-c596736d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bc2d4d...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in F2FS_RAW_SUPER fs/f2fs/f2fs.h:2000 [inline]
BUG: KASAN: slab-use-after-free in f2fs_record_stop_reason fs/f2fs/super.c:4047 [inline]
BUG: KASAN: slab-use-after-free in f2fs_record_error_work+0x41/0x1d0 fs/f2fs/super.c:4160
Read of size 8 at addr ffff888031090010 by task kworker/1:5/5869

CPU: 1 PID: 5869 Comm: kworker/1:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events f2fs_record_error_work
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xac/0x220 mm/kasan/report.c:468
kasan_report+0x117/0x150 mm/kasan/report.c:581
F2FS_RAW_SUPER fs/f2fs/f2fs.h:2000 [inline]
f2fs_record_stop_reason fs/f2fs/super.c:4047 [inline]
f2fs_record_error_work+0x41/0x1d0 fs/f2fs/super.c:4160
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>

Allocated by task 6610:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
f2fs_fill_super+0xc9/0x6cc0 fs/f2fs/super.c:4341
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 6610:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
__kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
f2fs_fill_super+0x3dad/0x6cc0 fs/f2fs/super.c:4809
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
insert_work+0x3d/0x310 kernel/workqueue.c:1651
__queue_work+0xc39/0x1020 kernel/workqueue.c:1800
queue_work_on+0x121/0x1e0 kernel/workqueue.c:1835
f2fs_submit_page_bio+0x1c3/0x650 fs/f2fs/data.c:694
__get_meta_page+0x18f/0x580 fs/f2fs/checkpoint.c:87
f2fs_get_meta_page fs/f2fs/checkpoint.c:112 [inline]
get_checkpoint_version+0x3c/0x330 fs/f2fs/checkpoint.c:851
validate_checkpoint+0x153/0x250 fs/f2fs/checkpoint.c:900
f2fs_get_valid_checkpoint+0x25e/0x940 fs/f2fs/checkpoint.c:939
f2fs_fill_super+0x3f3d/0x6cc0 fs/f2fs/super.c:4478
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888031090000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 16 bytes inside of
freed 8192-byte region [ffff888031090000, ffff888031092000)

The buggy address belongs to the physical page:
page:ffffea0000c42400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x31090
head:ffffea0000c42400 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017842280 ffffea0001802800 0000000000000004
raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6148, tgid 6144 (syz.3.107), ts 92657568595, free_ts 92595411814
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
alloc_slab_page+0x5d/0x170 mm/slub.c:1881
allocate_slab mm/slub.c:2028 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2081
___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
__slab_alloc mm/slub.c:3339 [inline]
__slab_alloc_node mm/slub.c:3392 [inline]
slab_alloc_node mm/slub.c:3485 [inline]
__kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3534
kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
kmalloc include/linux/slab.h:600 [inline]
audit_log_d_path+0xb5/0x190 kernel/audit.c:2150
audit_log_d_path_exe+0x45/0x70 kernel/audit.c:2221
audit_log_task+0x210/0x2e0 kernel/auditsc.c:2963
audit_seccomp+0x85/0x180 kernel/auditsc.c:3010
seccomp_log kernel/seccomp.c:1003 [inline]
__seccomp_filter+0xa62/0x1b80 kernel/seccomp.c:1290
syscall_trace_enter+0xa7/0x150 kernel/entry/common.c:72
do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:72
entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
__slab_free+0x35e/0x410 mm/slub.c:3736
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
slab_alloc_node mm/slub.c:3495 [inline]
slab_alloc mm/slub.c:3503 [inline]
__kmem_cache_alloc_lru mm/slub.c:3510 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
getname_flags+0xbb/0x500 fs/namei.c:140
getname fs/namei.c:219 [inline]
__do_sys_mkdir fs/namei.c:4164 [inline]
__se_sys_mkdir fs/namei.c:4162 [inline]
__x64_sys_mkdir+0x5f/0x80 fs/namei.c:4162
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
ffff88803108ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88803108ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888031090000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888031090080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888031090100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: c596736dadab Linux 6.6.120
git tree: linux-6.6.y

console output: https://syzkaller.appspot.com/x/log.txt?x=118485fc580000

kernel config: https://syzkaller.appspot.com/x/.config?x=691a6769a86ac817
dashboard link: https://syzkaller.appspot.com/bug?extid=bc2d4dea94357de41613
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1490059a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16354052580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/855c94eb3eef/disk-c596736d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b7510b30b774/vmlinux-c596736d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3ce7fe4f6991/bzImage-c596736d.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/6a03cb8eb8a4/mount_1.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1367599a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bc2d4d...@syzkaller.appspotmail.com

==================================================================

BUG: KASAN: slab-use-after-free in __up_write kernel/locking/rwsem.c:1364 [inline]
BUG: KASAN: slab-use-after-free in up_write+0x6b/0x410 kernel/locking/rwsem.c:1626
Read of size 8 at addr ffff88802ced0080 by task kworker/0:2/788

CPU: 0 PID: 788 Comm: kworker/0:2 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events f2fs_record_error_work
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xac/0x220 mm/kasan/report.c:468
kasan_report+0x117/0x150 mm/kasan/report.c:581

__up_write kernel/locking/rwsem.c:1364 [inline]
up_write+0x6b/0x410 kernel/locking/rwsem.c:1626
f2fs_up_write fs/f2fs/f2fs.h:2206 [inline]
f2fs_record_stop_reason fs/f2fs/super.c:4064 [inline]
f2fs_record_error_work+0x144/0x1d0 fs/f2fs/super.c:4160

process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>

Allocated by task 5928:

kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
f2fs_fill_super+0xc9/0x6cc0 fs/f2fs/super.c:4341
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3386
do_mount fs/namespace.c:3726 [inline]
__do_sys_mount fs/namespace.c:3935 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 5928:

The buggy address belongs to the object at ffff88802ced0000

which belongs to the cache kmalloc-8k of size 8192

The buggy address is located 128 bytes inside of
freed 8192-byte region [ffff88802ced0000, ffff88802ced2000)

The buggy address belongs to the physical page:

page:ffffea0000b3b400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ced0
head:ffffea0000b3b400 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0

flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()

raw: 00fff00000000840 ffff888017842280 ffffea0000abbe00 0000000000000002

raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5666, tgid 5666 (sshd-session), ts 68601777267, free_ts 68520694004

set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
alloc_slab_page+0x5d/0x170 mm/slub.c:1881
allocate_slab mm/slub.c:2028 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2081
___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
__slab_alloc mm/slub.c:3339 [inline]
__slab_alloc_node mm/slub.c:3392 [inline]
slab_alloc_node mm/slub.c:3485 [inline]
__kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3534
kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
kmalloc include/linux/slab.h:600 [inline]

kzalloc include/linux/slab.h:721 [inline]
tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
tomoyo_init_log+0x1104/0x1f10 security/tomoyo/audit.c:264
tomoyo_supervisor+0x32d/0x1080 security/tomoyo/common.c:2089
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x14a/0x1e0 security/tomoyo/environ.c:63
tomoyo_environ security/tomoyo/domain.c:672 [inline]
tomoyo_find_next_domain+0x1594/0x1a60 security/tomoyo/domain.c:881
tomoyo_bprm_check_security+0x116/0x170 security/tomoyo/tomoyo.c:101
security_bprm_check+0x62/0xa0 security/security.c:1103
search_binary_handler fs/exec.c:1763 [inline]
exec_binprm fs/exec.c:1817 [inline]
bprm_execve+0xa51/0x16f0 fs/exec.c:1892
do_execveat_common+0x51b/0x6c0 fs/exec.c:1998

page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429

discard_slab mm/slub.c:2127 [inline]
__unfreeze_partials+0x1cf/0x210 mm/slub.c:2667
put_cpu_partial+0x17c/0x250 mm/slub.c:2743
__slab_free+0x31d/0x410 mm/slub.c:3700

qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
slab_alloc_node mm/slub.c:3495 [inline]
slab_alloc mm/slub.c:3503 [inline]
__kmem_cache_alloc_lru mm/slub.c:3510 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519

ptlock_alloc mm/memory.c:6177 [inline]
ptlock_init include/linux/mm.h:2964 [inline]
pmd_ptlock_init include/linux/mm.h:3064 [inline]
pagetable_pmd_ctor include/linux/mm.h:3102 [inline]
pmd_alloc_one include/asm-generic/pgalloc.h:137 [inline]
__pmd_alloc+0x116/0x880 mm/memory.c:5599
pmd_alloc include/linux/mm.h:2863 [inline]
alloc_new_pmd mm/mremap.c:96 [inline]
move_page_tables+0x1758/0x1910 mm/mremap.c:555
shift_arg_pages fs/exec.c:713 [inline]
setup_arg_pages+0xb38/0xed0 fs/exec.c:836
load_elf_binary+0xb98/0x2700 fs/binfmt_elf.c:1045
search_binary_handler fs/exec.c:1775 [inline]
exec_binprm fs/exec.c:1817 [inline]
bprm_execve+0xaeb/0x16f0 fs/exec.c:1892
do_execveat_common+0x51b/0x6c0 fs/exec.c:1998

Memory state around the buggy address:

ffff88802cecff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802ced0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802ced0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802ced0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802ced0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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#syz test: git://repo/address.git branch-or-commit-hash
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