==================================================================
BUG: KASAN: use-after-free in fast_dput+0x1e9/0x290 fs/dcache.c:778
Read of size 4 at addr ffff888132cee220 by task syz.9.1114/4502
CPU: 0 PID: 4502 Comm: syz.9.1114 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x71/0x200 mm/kasan/report.c:316
print_report+0x4a/0x60 mm/kasan/report.c:420
kasan_report+0x122/0x150 mm/kasan/report.c:524
__asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350
fast_dput+0x1e9/0x290 fs/dcache.c:778
dput+0x21/0x80 fs/dcache.c:905
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003
deactivate_locked_super+0xb5/0x120 fs/super.c:336
deactivate_super+0xaf/0xe0 fs/super.c:367
cleanup_mnt+0x474/0x500 fs/namespace.c:1192
__cleanup_mnt+0x19/0x20 fs/namespace.c:1199
task_work_run+0x1e1/0x250 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa35/0x2660 kernel/exit.c:886
do_group_exit+0x225/0x2e0 kernel/exit.c:1029
get_signal+0x13b5/0x1520 kernel/signal.c:2891
arch_do_signal_or_restart+0xd1/0x1140 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f530bf5d68e
Code: Unable to access opcode bytes at 0x7f530bf5d664.
RSP: 002b:00007f530ce57f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f530ce586c0 RCX: 00007f530bf5d68e
RDX: 00007f530ce57fb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f530c032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f530c216128 R14: 00007f530c216090 R15: 00007ffebe26b598
Allocated by task 5067:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
__kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:334
kasan_slab_alloc include/linux/kasan.h:202 [inline]
slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
slab_alloc_node mm/slub.c:3382 [inline]
slab_alloc mm/slub.c:3392 [inline]
__kmem_cache_alloc_lru mm/slub.c:3399 [inline]
kmem_cache_alloc_lru+0x104/0x280 mm/slub.c:3415
__d_alloc+0x34/0x6c0 fs/dcache.c:1774
d_alloc fs/dcache.c:1854 [inline]
d_alloc_parallel+0xe2/0x12e0 fs/dcache.c:2647
__lookup_slow+0x14f/0x410 fs/namei.c:1682
lookup_one_len+0x19d/0x2e0 fs/namei.c:2747
incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210
open_or_create_special_dir+0x4f/0x1d0 fs/incfs/vfs.c:475
incfs_mount_fs+0x42f/0x890 fs/incfs/vfs.c:1890
legacy_get_tree+0xfe/0x1a0 fs/fs_context.c:632
vfs_get_tree+0x9a/0x270 fs/super.c:1578
do_new_mount+0x251/0xb30 fs/namespace.c:3081
path_mount+0x659/0xfc0 fs/namespace.c:3411
do_mount fs/namespace.c:3424 [inline]
__do_sys_mount fs/namespace.c:3632 [inline]
__se_sys_mount+0x320/0x390 fs/namespace.c:3609
__x64_sys_mount+0xbf/0xd0 fs/namespace.c:3609
x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 5083:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1750 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
slab_free mm/slub.c:3712 [inline]
kmem_cache_free+0x12d/0x300 mm/slub.c:3737
__d_free+0x23/0x30 fs/dcache.c:298
rcu_do_batch+0x52a/0xbc0 kernel/rcu/tree.c:2297
rcu_core+0x5c3/0xe80 kernel/rcu/tree.c:2557
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574
handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
__call_rcu_common kernel/rcu/tree.c:2807 [inline]
call_rcu+0xcf/0xf90 kernel/rcu/tree.c:2926
dentry_free+0xbd/0x150 fs/dcache.c:-1
__dentry_kill+0x529/0x670 fs/dcache.c:625
dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
dput+0x42/0x80 fs/dcache.c:918
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003
deactivate_locked_super+0xb5/0x120 fs/super.c:336
deactivate_super+0xaf/0xe0 fs/super.c:367
cleanup_mnt+0x474/0x500 fs/namespace.c:1192
__cleanup_mnt+0x19/0x20 fs/namespace.c:1199
task_work_run+0x1e1/0x250 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa35/0x2660 kernel/exit.c:886
do_group_exit+0x225/0x2e0 kernel/exit.c:1029
get_signal+0x13b5/0x1520 kernel/signal.c:2891
arch_do_signal_or_restart+0xd1/0x1140 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
__call_rcu_common kernel/rcu/tree.c:2807 [inline]
call_rcu+0xcf/0xf90 kernel/rcu/tree.c:2926
dentry_free+0xbd/0x150 fs/dcache.c:-1
__dentry_kill+0x529/0x670 fs/dcache.c:625
dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
dput+0x42/0x80 fs/dcache.c:918
do_unlinkat+0x34a/0x6d0 fs/namei.c:4400
__do_sys_unlink fs/namei.c:4445 [inline]
__se_sys_unlink fs/namei.c:4443 [inline]
__x64_sys_unlink+0x49/0x50 fs/namei.c:4443
x64_sys_call+0x958/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:88
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888132cee220
which belongs to the cache dentry of size 208
The buggy address is located 0 bytes inside of
208-byte region [ffff888132cee220, ffff888132cee2f0)
The buggy address belongs to the physical page:
page:ffffea0004cb3b80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x132cee
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 dead000000000100 dead000000000122 ffff8881001ec000
raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x112cd0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 359, tgid 354 (syz.3.10), ts 30934407658, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4585
__alloc_pages+0x1fa/0x610 mm/page_alloc.c:5929
alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
allocate_slab mm/slub.c:1967 [inline]
new_slab+0x98/0x3d0 mm/slub.c:2020
___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
__slab_alloc+0x5e/0xa0 mm/slub.c:3263
slab_alloc_node mm/slub.c:3348 [inline]
slab_alloc mm/slub.c:3392 [inline]
__kmem_cache_alloc_lru mm/slub.c:3399 [inline]
kmem_cache_alloc_lru+0x144/0x280 mm/slub.c:3415
__d_alloc+0x34/0x6c0 fs/dcache.c:1774
d_alloc fs/dcache.c:1854 [inline]
d_alloc_parallel+0xe2/0x12e0 fs/dcache.c:2647
__lookup_slow+0x14f/0x410 fs/namei.c:1682
lookup_one_len+0x19d/0x2e0 fs/namei.c:2747
start_creating+0x167/0x2f0 fs/debugfs/inode.c:377
__debugfs_create_file+0x78/0x510 fs/debugfs/inode.c:422
debugfs_create_file+0x4a/0x60 fs/debugfs/inode.c:489
page_owner free stack trace missing
Memory state around the buggy address:
ffff888132cee100: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888132cee180: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888132cee200: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb
^
ffff888132cee280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
ffff888132cee300: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4502 at fs/dcache.c:794 fast_dput+0x210/0x290 fs/dcache.c:794
Modules linked in:
CPU: 0 PID: 4502 Comm: syz.9.1114 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:fast_dput+0x210/0x290 fs/dcache.c:794
Code: 97 f1 ff e9 46 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 99 fe ff ff 48 89 df e8 5a 97 f1 ff e9 8c fe ff ff e8 50 f2 ab ff <0f> 0b e9 0b ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c e4 fe ff
RSP: 0018:ffffc90008b87790 EFLAGS: 00010293
RAX: ffffffff81c58930 RBX: ffff888132cee220 RCX: ffff888117dd2880
RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001
RBP: ffffc90008b877c0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001170ee4 R12: 00000000ffffff80
R13: dffffc0000000000 R14: ffff888132cee278 R15: 1ffff1102659dc4f
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001145f1000 CR4: 00000000003506b0
Call Trace:
dput+0x21/0x80 fs/dcache.c:905
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003
deactivate_locked_super+0xb5/0x120 fs/super.c:336
deactivate_super+0xaf/0xe0 fs/super.c:367
cleanup_mnt+0x474/0x500 fs/namespace.c:1192
__cleanup_mnt+0x19/0x20 fs/namespace.c:1199
task_work_run+0x1e1/0x250 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa35/0x2660 kernel/exit.c:886
do_group_exit+0x225/0x2e0 kernel/exit.c:1029
get_signal+0x13b5/0x1520 kernel/signal.c:2891
arch_do_signal_or_restart+0xd1/0x1140 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f530bf5d68e
Code: Unable to access opcode bytes at 0x7f530bf5d664.
RSP: 002b:00007f530ce57f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f530ce586c0 RCX: 00007f530bf5d68e
RDX: 00007f530ce57fb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f530c032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f530c216128 R14: 00007f530c216090 R15: 00007ffebe26b598
---[ end trace 0000000000000000 ]---
list_del corruption. prev->next should be ffff888132ceeb30, but was ffff888132ceec40. (prev=ffff8881418fb2c0)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:61!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4502 Comm: syz.9.1114 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__list_del_entry_valid+0x10f/0x130 lib/list_debug.c:59
Code: e8 de 41 89 02 0f 0b 48 c7 c7 20 95 ca 85 48 89 de e8 cd 41 89 02 0f 0b 48 c7 c7 80 95 ca 85 48 89 de 4c 89 f9 e8 b9 41 89 02 <0f> 0b 48 c7 c7 00 96 ca 85 48 89 de 4c 89 f1 e8 a5 41 89 02 0f 0b
RSP: 0018:ffffc90008b87708 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888132ceeb30 RCX: 8e560dc929bdfc00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc90008b87728 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001170e30 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888132ceec40 R15: ffff8881418fb2c0
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000700f000 CR4: 00000000003506b0
Call Trace:
__list_del_entry include/linux/list.h:134 [inline]
dentry_unlist fs/dcache.c:554 [inline]
__dentry_kill+0x25d/0x670 fs/dcache.c:607
dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
dput+0x42/0x80 fs/dcache.c:918
incfs_free_mount_info+0x80/0x200 fs/incfs/data_mgmt.c:167
incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003
deactivate_locked_super+0xb5/0x120 fs/super.c:336
deactivate_super+0xaf/0xe0 fs/super.c:367
cleanup_mnt+0x474/0x500 fs/namespace.c:1192
__cleanup_mnt+0x19/0x20 fs/namespace.c:1199
task_work_run+0x1e1/0x250 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa35/0x2660 kernel/exit.c:886
do_group_exit+0x225/0x2e0 kernel/exit.c:1029
get_signal+0x13b5/0x1520 kernel/signal.c:2891
arch_do_signal_or_restart+0xd1/0x1140 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f530bf5d68e
Code: Unable to access opcode bytes at 0x7f530bf5d664.
RSP: 002b:00007f530ce57f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f530ce586c0 RCX: 00007f530bf5d68e
RDX: 00007f530ce57fb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f530c032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f530c216128 R14: 00007f530c216090 R15: 00007ffebe26b598
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid+0x10f/0x130 lib/list_debug.c:59
Code: e8 de 41 89 02 0f 0b 48 c7 c7 20 95 ca 85 48 89 de e8 cd 41 89 02 0f 0b 48 c7 c7 80 95 ca 85 48 89 de 4c 89 f9 e8 b9 41 89 02 <0f> 0b 48 c7 c7 00 96 ca 85 48 89 de 4c 89 f1 e8 a5 41 89 02 0f 0b
RSP: 0018:ffffc90008b87708 EFLAGS: 00010246
RAX: 000000000000006d RBX: ffff888132ceeb30 RCX: 8e560dc929bdfc00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc90008b87728 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001170e30 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888132ceec40 R15: ffff8881418fb2c0
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000700f000 CR4: 00000000003506b0