==================================================================
BUG: KASAN: use-after-free in fast_dput+0x1e0/0x290 fs/dcache.c:753
Read of size 4 at addr ffff888112c4bcc0 by task syz-executor/711
CPU: 0 PID: 711 Comm: syz-executor Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:427 [inline]
kasan_report+0x10f/0x150 mm/kasan/report.c:444
__asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
fast_dput+0x1e0/0x290 fs/dcache.c:753
dput+0x26/0x90 fs/dcache.c:880
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1af/0x210 fs/incfs/vfs.c:1997
deactivate_locked_super+0xa0/0x100 fs/super.c:335
deactivate_super+0xaf/0xe0 fs/super.c:366
cleanup_mnt+0x44f/0x500 fs/namespace.c:1149
__cleanup_mnt+0x19/0x20 fs/namespace.c:1156
task_work_run+0x127/0x190 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0xb70/0x29a0 kernel/exit.c:890
do_group_exit+0x149/0x310 kernel/exit.c:1004
__do_sys_exit_group kernel/exit.c:1015 [inline]
__se_sys_exit_group kernel/exit.c:1013 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f55e9fe5e99
Code: Unable to access opcode bytes at RIP 0x7f55e9fe5e6f.
RSP: 002b:00007ffe7bf24318 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f55ea07b36a RCX: 00007f55e9fe5e99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f55ea07b30a
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe7bf255d0
R13: 00007f55ea07b30a R14: 00005555657344e8 R15: 00007ffe7bf266a0
Allocated by task 819:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:433 [inline]
__kasan_slab_alloc+0xb7/0xe0 mm/kasan/common.c:466
kasan_slab_alloc include/linux/kasan.h:217 [inline]
slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
slab_alloc_node mm/slub.c:3245 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260
__d_alloc+0x2d/0x690 fs/dcache.c:1749
d_alloc fs/dcache.c:1828 [inline]
d_alloc_parallel+0xe5/0x1380 fs/dcache.c:2584
__lookup_slow+0x14c/0x410 fs/namei.c:1656
lookup_one_len+0x19d/0x2d0 fs/namei.c:2726
incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210
open_or_create_special_dir+0x4c/0x1f0 fs/incfs/vfs.c:475
incfs_mount_fs+0x42f/0x890 fs/incfs/vfs.c:1884
legacy_get_tree+0xed/0x190 fs/fs_context.c:611
vfs_get_tree+0x89/0x260 fs/super.c:1530
do_new_mount+0x251/0xb40 fs/namespace.c:3037
path_mount+0x640/0xff0 fs/namespace.c:3367
do_mount fs/namespace.c:3380 [inline]
__do_sys_mount fs/namespace.c:3588 [inline]
__se_sys_mount+0x320/0x390 fs/namespace.c:3565
__x64_sys_mount+0xbf/0xd0 fs/namespace.c:3565
x64_sys_call+0x6bf/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Freed by task 25:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
kasan_slab_free include/linux/kasan.h:193 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
slab_free mm/slub.c:3526 [inline]
kmem_cache_free+0x100/0x320 mm/slub.c:3544
__d_free+0x23/0x30 fs/dcache.c:273
rcu_do_batch+0x4c1/0xbf0 kernel/rcu/tree.c:2523
rcu_core+0x4a3/0xef0 kernel/rcu/tree.c:2763
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776
handle_softirqs+0x250/0x560 kernel/softirq.c:583
run_ksoftirqd+0x28/0x40 kernel/softirq.c:959
smpboot_thread_fn+0x446/0x880 kernel/smpboot.c:164
kthread+0x3f5/0x4f0 kernel/kthread.c:337
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu_common kernel/rcu/tree.c:3011 [inline]
call_rcu+0x10b/0xf60 kernel/rcu/tree.c:3129
dentry_free+0xbd/0x150 fs/dcache.c:-1
__dentry_kill+0x516/0x660 fs/dcache.c:600
dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
dput+0x47/0x90 fs/dcache.c:893
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1af/0x210 fs/incfs/vfs.c:1997
deactivate_locked_super+0xa0/0x100 fs/super.c:335
deactivate_super+0xaf/0xe0 fs/super.c:366
cleanup_mnt+0x44f/0x500 fs/namespace.c:1149
__cleanup_mnt+0x19/0x20 fs/namespace.c:1156
task_work_run+0x127/0x190 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0xb70/0x29a0 kernel/exit.c:890
do_group_exit+0x149/0x310 kernel/exit.c:1004
__do_sys_exit_group kernel/exit.c:1015 [inline]
__se_sys_exit_group kernel/exit.c:1013 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu_common kernel/rcu/tree.c:3011 [inline]
call_rcu+0x10b/0xf60 kernel/rcu/tree.c:3129
dentry_free+0xbd/0x150 fs/dcache.c:-1
__dentry_kill+0x516/0x660 fs/dcache.c:600
dentry_kill+0xc0/0x2a0 fs/dcache.c:-1
dput+0x47/0x90 fs/dcache.c:893
do_renameat2+0xa33/0xfc0 fs/namei.c:4995
__do_sys_rename fs/namei.c:5039 [inline]
__se_sys_rename fs/namei.c:5037 [inline]
__x64_sys_rename+0x86/0x90 fs/namei.c:5037
x64_sys_call+0x680/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:83
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
The buggy address belongs to the object at ffff888112c4bcc0
which belongs to the cache dentry of size 208
The buggy address is located 0 bytes inside of
208-byte region [ffff888112c4bcc0, ffff888112c4bd90)
The buggy address belongs to the page:
page:ffffea00044b12c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112c4b
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 0000000300000001 ffff8881001c5c80
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 0x12cd0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 106, ts 4420553558, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
__alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1937 [inline]
new_slab+0xa0/0x4d0 mm/slub.c:2000
___slab_alloc+0x3ac/0x840 mm/slub.c:3033
__slab_alloc+0x49/0x90 mm/slub.c:3120
slab_alloc_node mm/slub.c:3211 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc+0x138/0x260 mm/slub.c:3260
__d_alloc+0x2d/0x690 fs/dcache.c:1749
d_alloc+0x48/0x260 fs/dcache.c:1828
lookup_one_qstr_excl+0xcb/0x250 fs/namei.c:1567
do_renameat2+0x650/0xfc0 fs/namei.c:4943
__do_sys_rename fs/namei.c:5039 [inline]
__se_sys_rename fs/namei.c:5037 [inline]
__x64_sys_rename+0x86/0x90 fs/namei.c:5037
x64_sys_call+0x680/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:83
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
page_owner free stack trace missing
Memory state around the buggy address:
ffff888112c4bb80: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
ffff888112c4bc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888112c4bc80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
^
ffff888112c4bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888112c4bd80: fb fb fc fc fc fc fc fc fc fc 00 00 00 00 00 00
==================================================================
------------[ cut here ]------------
WARNING: CPU: 0 PID: 711 at fs/dcache.c:769 fast_dput+0x207/0x290 fs/dcache.c:769
Modules linked in:
CPU: 0 PID: 711 Comm: syz-executor Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
RIP: 0010:fast_dput+0x207/0x290 fs/dcache.c:769
Code: ed f2 ff e9 4e fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a1 fe ff ff 48 89 df e8 e3 ec f2 ff e9 94 fe ff ff e8 49 7b b3 ff <0f> 0b e9 13 ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ec fe ff
RSP: 0018:ffffc90000be7b60 EFLAGS: 00010293
RAX: ffffffff81b63b57 RBX: ffff888112c4bcc0 RCX: ffff8881285a2780
RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001
RBP: ffffc90000be7b88 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200017cf5c R12: 00000000ffffff80
R13: dffffc0000000000 R14: ffff888112c4bd18 R15: 1ffff110225897a3
FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f080e6320f8 CR3: 000000010d7c2000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
dput+0x26/0x90 fs/dcache.c:880
incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166
incfs_kill_sb+0x1af/0x210 fs/incfs/vfs.c:1997
deactivate_locked_super+0xa0/0x100 fs/super.c:335
deactivate_super+0xaf/0xe0 fs/super.c:366
cleanup_mnt+0x44f/0x500 fs/namespace.c:1149
__cleanup_mnt+0x19/0x20 fs/namespace.c:1156
task_work_run+0x127/0x190 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0xb70/0x29a0 kernel/exit.c:890
do_group_exit+0x149/0x310 kernel/exit.c:1004
__do_sys_exit_group kernel/exit.c:1015 [inline]
__se_sys_exit_group kernel/exit.c:1013 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f55e9fe5e99
Code: Unable to access opcode bytes at RIP 0x7f55e9fe5e6f.
RSP: 002b:00007ffe7bf24318 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f55ea07b36a RCX: 00007f55e9fe5e99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f55ea07b30a
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe7bf255d0
R13: 00007f55ea07b30a R14: 00005555657344e8 R15: 00007ffe7bf266a0
---[ end trace cff2ec90b2fd42a6 ]---