R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffc40290e90
R13: 00007fe724613d7d R14: 00005555763ba4a8 R15: 00007ffc40291f60
---[ end trace 0000000000000000 ]---
==================================================================
BUG: KASAN: use-after-free in fast_dput+0x1e9/0x290 fs/dcache.c:778
Read of size 4 at addr ffff888132f70cc0 by task syz-executor/284
CPU: 1 PID: 284 Comm: syz-executor Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:88
dump_stack_lvl+0xee/0x150 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:334
deactivate_super+0xaf/0xe0 fs/super.c:365
cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1191
__cleanup_mnt+0x19/0x20 fs/namespace.c:1198
task_work_run+0x1db/0x240 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa25/0x2650 kernel/exit.c:886
do_group_exit+0x210/0x2d0 kernel/exit.c:1028
__do_sys_exit_group kernel/exit.c:1039 [inline]
__se_sys_exit_group kernel/exit.c:1037 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1037
x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe72458f749
Code: Unable to access opcode bytes at 0x7fe72458f71f.
RSP: 002b:00007ffc4028fbd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fe724613ddd RCX: 00007fe72458f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000009 R08: 00007ffc4028d977 R09: 00007ffc40290e90
R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffc40290e90
R13: 00007fe724613d7d R14: 00005555763ba4a8 R15: 00007ffc40291f60
Allocated by task 3880:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
__kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:333
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+0xd6/0x1240 fs/dcache.c:2645
__lookup_slow+0x141/0x3f0 fs/namei.c:1682
lookup_one_len+0x195/0x2d0 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/0x880 fs/incfs/vfs.c:1890
legacy_get_tree+0xfe/0x1a0 fs/fs_context.c:632
vfs_get_tree+0x9a/0x270 fs/super.c:1575
do_new_mount+0x25a/0xa20 fs/namespace.c:3078
path_mount+0x675/0x1010 fs/namespace.c:3408
do_mount fs/namespace.c:3421 [inline]
__do_sys_mount fs/namespace.c:3629 [inline]
__se_sys_mount+0x318/0x380 fs/namespace.c:3606
__x64_sys_mount+0xbf/0xd0 fs/namespace.c:3606
x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 0:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x132/0x180 mm/kasan/common.c:241
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:249
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+0x515/0xb90 kernel/rcu/tree.c:2297
rcu_core+0x5a5/0xe70 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:45
__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+0xd4/0xf90 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:334
deactivate_super+0xaf/0xe0 fs/super.c:365
cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1191
__cleanup_mnt+0x19/0x20 fs/namespace.c:1198
task_work_run+0x1db/0x240 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa25/0x2650 kernel/exit.c:886
do_group_exit+0x210/0x2d0 kernel/exit.c:1028
__do_sys_exit_group kernel/exit.c:1039 [inline]
__se_sys_exit_group kernel/exit.c:1037 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1037
x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
__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+0xd4/0xf90 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+0x33f/0x6b0 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:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888132f70cc0
which belongs to the cache dentry of size 208
The buggy address is located 0 bytes inside of
208-byte region [ffff888132f70cc0, ffff888132f70d90)
The buggy address belongs to the physical page:
page:ffffea0004cbdc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x132f70
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000001 ffff8881001ed080
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 587, tgid 586 (syz.2.60), ts 37636311084, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
get_page_from_freelist+0x2c7b/0x2cf0 mm/page_alloc.c:4554
__alloc_pages+0x1c3/0x450 mm/page_alloc.c:5868
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+0xd6/0x1240 fs/dcache.c:2645
__lookup_slow+0x141/0x3f0 fs/namei.c:1682
lookup_one_len+0x195/0x2d0 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:
ffff888132f70b80: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
ffff888132f70c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888132f70c80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
^
ffff888132f70d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888132f70d80: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 284 at fs/dcache.c:794 fast_dput+0x210/0x290 fs/dcache.c:794
Modules linked in:
CPU: 1 PID: 284 Comm: syz-executor Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:fast_dput+0x210/0x290 fs/dcache.c:794
Code: d4 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 6a d4 f1 ff e9 8c fe ff ff e8 00 5b ad 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:ffffc9000d2cfad0 EFLAGS: 00010293
RAX: ffffffff81c2cf80 RBX: ffff888132f70cc0 RCX: ffff88810e30a880
RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001
RBP: ffffc9000d2cfb00 R08: 0000000000000004 R09: 0000000000000003
R10: fffff52001a59f4c R11: 1ffff92001a59f4c R12: 00000000ffffff80
R13: dffffc0000000000 R14: ffff888132f70d18 R15: 1ffff110265ee1a3
FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ed1eff8 CR3: 0000000133f97000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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:334
deactivate_super+0xaf/0xe0 fs/super.c:365
cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1191
__cleanup_mnt+0x19/0x20 fs/namespace.c:1198
task_work_run+0x1db/0x240 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa25/0x2650 kernel/exit.c:886
do_group_exit+0x210/0x2d0 kernel/exit.c:1028
__do_sys_exit_group kernel/exit.c:1039 [inline]
__se_sys_exit_group kernel/exit.c:1037 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1037
x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe72458f749
Code: Unable to access opcode bytes at 0x7fe72458f71f.
RSP: 002b:00007ffc4028fbd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fe724613ddd RCX: 00007fe72458f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000009 R08: 00007ffc4028d977 R09: 00007ffc40290e90
R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffc40290e90
R13: 00007fe724613d7d R14: 00005555763ba4a8 R15: 00007ffc40291f60
---[ end trace 0000000000000000 ]---
BUG: unable to handle page fault for address: fffffffffffffffc
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 6e12067 P4D 6e12067 PUD 6e14067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 284 Comm: syz-executor Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__dentry_kill+0xd0/0x670 fs/dcache.c:599
Code: ff 4d 8b 36 49 83 c6 38 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 cc be f1 ff 48 89 df 4d 8b 1e 41 ba ee 71 7a d4 <45> 03 53 fc 74 02 0f 0b 41 ff d3 43 0f b6 04 2c 84 c0 0f 85 b3 04
RSP: 0018:ffffc9000d2cfa78 EFLAGS: 00010246
RAX: 1ffffffff0b22357 RBX: ffff888132f70330 RCX: ffffffff81c2e527
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888132f70330
RBP: ffffc9000d2cfac0 R08: fffffffffffffffb R09: 0000000000000003
R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff110265ee066
R13: dffffc0000000000 R14: ffffffff85911ab8 R15: ffff888132f70388
FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffc CR3: 000000013296d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
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:334
deactivate_super+0xaf/0xe0 fs/super.c:365
cleanup_mnt+0x45f/0x4e0 fs/namespace.c:1191
__cleanup_mnt+0x19/0x20 fs/namespace.c:1198
task_work_run+0x1db/0x240 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xa25/0x2650 kernel/exit.c:886
do_group_exit+0x210/0x2d0 kernel/exit.c:1028
__do_sys_exit_group kernel/exit.c:1039 [inline]
__se_sys_exit_group kernel/exit.c:1037 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1037
x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe72458f749
Code: Unable to access opcode bytes at 0x7fe72458f71f.
RSP: 002b:00007ffc4028fbd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fe724613ddd RCX: 00007fe72458f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000009 R08: 00007ffc4028d977 R09: 00007ffc40290e90
R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffc40290e90
R13: 00007fe724613d7d R14: 00005555763ba4a8 R15: 00007ffc40291f60
Modules linked in:
CR2: fffffffffffffffc
---[ end trace 0000000000000000 ]---
RIP: 0010:__dentry_kill+0xd0/0x670 fs/dcache.c:599
Code: ff 4d 8b 36 49 83 c6 38 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 cc be f1 ff 48 89 df 4d 8b 1e 41 ba ee 71 7a d4 <45> 03 53 fc 74 02 0f 0b 41 ff d3 43 0f b6 04 2c 84 c0 0f 85 b3 04
RSP: 0018:ffffc9000d2cfa78 EFLAGS: 00010246
RAX: 1ffffffff0b22357 RBX: ffff888132f70330 RCX: ffffffff81c2e527
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888132f70330
RBP: ffffc9000d2cfac0 R08: fffffffffffffffb R09: 0000000000000003
R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff110265ee066
R13: dffffc0000000000 R14: ffffffff85911ab8 R15: ffff888132f70388
FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffc CR3: 000000013296d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: ff 4d 8b decl -0x75(%rbp)
3: 36 49 83 c6 38 ss add $0x38,%r14
8: 4c 89 f0 mov %r14,%rax
b: 48 c1 e8 03 shr $0x3,%rax
f: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
14: 74 08 je 0x1e
16: 4c 89 f7 mov %r14,%rdi
19: e8 cc be f1 ff call 0xfff1beea
1e: 48 89 df mov %rbx,%rdi
21: 4d 8b 1e mov (%r14),%r11
24: 41 ba ee 71 7a d4 mov $0xd47a71ee,%r10d
* 2a: 45 03 53 fc add -0x4(%r11),%r10d <-- trapping instruction
2e: 74 02 je 0x32
30: 0f 0b ud2
32: 41 ff d3 call *%r11
35: 43 0f b6 04 2c movzbl (%r12,%r13,1),%eax
3a: 84 c0 test %al,%al
3c: 0f .byte 0xf
3d: 85 .byte 0x85
3e: b3 04 mov $0x4,%bl