------------[ cut here ]------------
WARNING: CPU: 1 PID: 400 at fs/inode.c:340 drop_nlink+0xce/0x110 fs/inode.c:340
Modules linked in:
CPU: 1 UID: 0 PID: 400 Comm: syz.0.16 Not tainted syzkaller #0 d64b2f5a4faec06c76b1c009cdccbf3bdfb2fff1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:drop_nlink+0xce/0x110 fs/inode.c:340
Code: 04 00 00 be 08 00 00 00 e8 4f 14 ee ff f0 48 ff 83 b8 04 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 d2 5d 95 ff <0f> 0b eb 81 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 59 ff ff ff 4c
RSP: 0000:ffffc9000d9df888 EFLAGS: 00010293
RAX: ffffffff81f211fe RBX: ffff88812141d040 RCX: ffff8881157c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000d9df8b0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001b3bf08 R12: dffffc0000000000
R13: 1ffff11024283a11 R14: ffff88812141d088 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002840 CR3: 00000000074aa000 CR4: 00000000003526b0
Call Trace:
simple_rmdir+0x152/0x260 fs/libfs.c:773
vfs_rmdir+0x3de/0x560 fs/namei.c:4348
incfs_kill_sb+0x102/0x220 fs/incfs/vfs.c:1968
deactivate_locked_super+0xd5/0x270 fs/super.c:478
deactivate_super+0xb8/0xe0 fs/super.c:511
cleanup_mnt+0x438/0x4d0 fs/namespace.c:1380
__cleanup_mnt+0x1d/0x40 fs/namespace.c:1387
task_work_run+0x1e8/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:955
do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
get_signal+0x134c/0x1490 kernel/signal.c:2933
arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x4d/0xb0 kernel/entry/common.c:231
irqentry_exit+0x16/0x60 kernel/entry/common.c:334
exc_page_fault+0x65/0xc0 arch/x86/mm/fault.c:1537
asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f279379ce61
Code: Unable to access opcode bytes at 0x7f279379ce37.
RSP: 002b:fffffffffffffc70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f2793a15fa0 RCX: 00007f279379ce59
RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000
RBP: 00007f2793832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f2793a16038 R14: 00007f2793a15fa0 R15: 00007ffe839030b8
---[ end trace 0000000000000000 ]---
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: null-ptr-deref in atomic_inc_return include/linux/atomic/atomic-instrumented.h:453 [inline]
BUG: KASAN: null-ptr-deref in ihold+0x24/0x70 fs/inode.c:452
Write of size 4 at addr 0000000000000168 by task syz.0.16/400
CPU: 0 UID: 0 PID: 400 Comm: syz.0.16 Tainted: G W syzkaller #0 d64b2f5a4faec06c76b1c009cdccbf3bdfb2fff1
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
print_report+0x3d/0x70 mm/kasan/report.c:484
kasan_report+0x162/0x1a0 mm/kasan/report.c:594
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x25a/0x2b0 mm/kasan/generic.c:189
__kasan_check_write+0x18/0x20 mm/kasan/shadow.c:37
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_inc_return include/linux/atomic/atomic-instrumented.h:453 [inline]
ihold+0x24/0x70 fs/inode.c:452
d_delete_notify include/linux/fsnotify.h:357 [inline]
vfs_rmdir+0x25c/0x560 fs/namei.c:4361
incfs_kill_sb+0x102/0x220 fs/incfs/vfs.c:1968
deactivate_locked_super+0xd5/0x270 fs/super.c:478
deactivate_super+0xb8/0xe0 fs/super.c:511
cleanup_mnt+0x438/0x4d0 fs/namespace.c:1380
__cleanup_mnt+0x1d/0x40 fs/namespace.c:1387
task_work_run+0x1e8/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:955
do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
get_signal+0x134c/0x1490 kernel/signal.c:2933
arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x4d/0xb0 kernel/entry/common.c:231
irqentry_exit+0x16/0x60 kernel/entry/common.c:334
exc_page_fault+0x65/0xc0 arch/x86/mm/fault.c:1537
asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f279379ce61
Code: Unable to access opcode bytes at 0x7f279379ce37.
RSP: 002b:fffffffffffffc70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f2793a15fa0 RCX: 00007f279379ce59
RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000
RBP: 00007f2793832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f2793a16038 R14: 00007f2793a15fa0 R15: 00007ffe839030b8
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000168
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 8000000132431067 P4D 8000000132431067 PUD 0
Oops: Oops: 0002 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 400 Comm: syz.0.16 Tainted: G B W syzkaller #0 d64b2f5a4faec06c76b1c009cdccbf3bdfb2fff1
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:85 [inline]
RIP: 0010:raw_atomic_add_return include/linux/atomic/atomic-arch-fallback.h:564 [inline]
RIP: 0010:raw_atomic_inc_return include/linux/atomic/atomic-arch-fallback.h:1020 [inline]
RIP: 0010:atomic_inc_return include/linux/atomic/atomic-instrumented.h:454 [inline]
RIP: 0010:ihold+0x2a/0x70 fs/inode.c:452
Code: f3 0f 1e fa 55 48 89 e5 41 56 53 48 89 fb e8 bd 54 95 ff 48 8d bb 68 01 00 00 be 04 00 00 00 e8 0c 0b ee ff 41 be 01 00 00 00 44 0f c1 b3 68 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 cd
RSP: 0018:ffffc9000d9df8e8 EFLAGS: 00010246
RAX: ffff8881157c0000 RBX: 0000000000000000 RCX: ffff8881157c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000d9df8f8 R08: ffffffff88bb2947 R09: 1ffffffff1176528
R10: dffffc0000000000 R11: fffffbfff1176529 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000168 CR3: 000000012a01c000 CR4: 00000000003526b0
Call Trace:
d_delete_notify include/linux/fsnotify.h:357 [inline]
vfs_rmdir+0x25c/0x560 fs/namei.c:4361
incfs_kill_sb+0x102/0x220 fs/incfs/vfs.c:1968
deactivate_locked_super+0xd5/0x270 fs/super.c:478
deactivate_super+0xb8/0xe0 fs/super.c:511
cleanup_mnt+0x438/0x4d0 fs/namespace.c:1380
__cleanup_mnt+0x1d/0x40 fs/namespace.c:1387
task_work_run+0x1e8/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:955
do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
get_signal+0x134c/0x1490 kernel/signal.c:2933
arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x4d/0xb0 kernel/entry/common.c:231
irqentry_exit+0x16/0x60 kernel/entry/common.c:334
exc_page_fault+0x65/0xc0 arch/x86/mm/fault.c:1537
asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f279379ce61
Code: Unable to access opcode bytes at 0x7f279379ce37.
RSP: 002b:fffffffffffffc70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f2793a15fa0 RCX: 00007f279379ce59
RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000
RBP: 00007f2793832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f2793a16038 R14: 00007f2793a15fa0 R15: 00007ffe839030b8
Modules linked in:
CR2: 0000000000000168
---[ end trace 0000000000000000 ]---
RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:85 [inline]
RIP: 0010:raw_atomic_add_return include/linux/atomic/atomic-arch-fallback.h:564 [inline]
RIP: 0010:raw_atomic_inc_return include/linux/atomic/atomic-arch-fallback.h:1020 [inline]
RIP: 0010:atomic_inc_return include/linux/atomic/atomic-instrumented.h:454 [inline]
RIP: 0010:ihold+0x2a/0x70 fs/inode.c:452
Code: f3 0f 1e fa 55 48 89 e5 41 56 53 48 89 fb e8 bd 54 95 ff 48 8d bb 68 01 00 00 be 04 00 00 00 e8 0c 0b ee ff 41 be 01 00 00 00 44 0f c1 b3 68 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 cd
RSP: 0018:ffffc9000d9df8e8 EFLAGS: 00010246
RAX: ffff8881157c0000 RBX: 0000000000000000 RCX: ffff8881157c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000d9df8f8 R08: ffffffff88bb2947 R09: 1ffffffff1176528
R10: dffffc0000000000 R11: fffffbfff1176529 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000168 CR3: 000000012a01c000 CR4: 00000000003526b0
----------------
Code disassembly (best guess):
0: f3 0f 1e fa endbr64
4: 55 push %rbp
5: 48 89 e5 mov %rsp,%rbp
8: 41 56 push %r14
a: 53 push %rbx
b: 48 89 fb mov %rdi,%rbx
e: e8 bd 54 95 ff call 0xff9554d0
13: 48 8d bb 68 01 00 00 lea 0x168(%rbx),%rdi
1a: be 04 00 00 00 mov $0x4,%esi
1f: e8 0c 0b ee ff call 0xffee0b30
24: 41 be 01 00 00 00 mov $0x1,%r14d
* 2a: f0 44 0f c1 b3 68 01 lock xadd %r14d,0x168(%rbx) <-- trapping instruction
31: 00 00
33: 41 ff c6 inc %r14d
36: bf 02 00 00 00 mov $0x2,%edi
3b: 44 89 f6 mov %r14d,%esi
3e: e8 .byte 0xe8
3f: cd .byte 0xcd