syzbot
WARNING in simple_rmdir
Status:
premoderation: reported C repro on 2025/06/30 05:26
Bug presence:
origin:downstream
[Documentation on labels]
Reported-by: syzbot+51a1a87f6626bdbe1348@syzkaller.appspotmail.com
First crash: 487d, last: 2h20m
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Last patch testing requests (8)
Sample crash report:
soft_limit_in_bytes is deprecated and will be removed. Please report your usecase to linux-mm@kvack.org if you depend on this functionality.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 314 at fs/inode.c:340 drop_nlink+0xce/0x110 fs/inode.c:340
Modules linked in:
CPU: 0 UID: 0 PID: 314 Comm: syz-executor116 Not tainted syzkaller #0 ca18b34a931c0a5bfcb0703d5cd6c5f88dc9958b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:drop_nlink+0xce/0x110 fs/inode.c:340
Code: 04 00 00 be 08 00 00 00 e8 ff 0b ee ff f0 48 ff 83 b8 04 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 48 79 b5 03 cc e8 12 21 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: 0018:ffffc9000120fac8 EFLAGS: 00010293
RAX: ffffffff81f2585e RBX: ffff888126b42a40 RCX: ffff888121c8a600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000120faf0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000241f50 R12: dffffc0000000000
R13: 1ffff11024d68551 R14: ffff888126b42a88 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c7f1a9dbc CR3: 00000000074aa000 CR4: 00000000003526b0
Call Trace:
<TASK>
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:1970
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+0x1e5/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:961
do_group_exit+0x21f/0x2f0 kernel/exit.c:1104
__do_sys_exit_group kernel/exit.c:1115 [inline]
__se_sys_exit_group kernel/exit.c:1113 [inline]
__x64_sys_exit_group+0x43/0x50 kernel/exit.c:1113
x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7c7f141c45
Code: Unable to access opcode bytes at 0x7f7c7f141c1b.
RSP: 002b:00007ffd677f8878 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f7c7f141c45
RDX: 00000000000000e7 RSI: ffffffffffffffd8 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000001
R13: 00007f7c7f1db100 R14: 00007f7c7f1dd3a8 R15: 00007f7c7f1dd3c0
</TASK>
---[ 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-executor116/314
CPU: 1 UID: 0 PID: 314 Comm: syz-executor116 Tainted: G W syzkaller #0 ca18b34a931c0a5bfcb0703d5cd6c5f88dc9958b
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
__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:1970
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+0x1e5/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:961
do_group_exit+0x21f/0x2f0 kernel/exit.c:1104
__do_sys_exit_group kernel/exit.c:1115 [inline]
__se_sys_exit_group kernel/exit.c:1113 [inline]
__x64_sys_exit_group+0x43/0x50 kernel/exit.c:1113
x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7c7f141c45
Code: Unable to access opcode bytes at 0x7f7c7f141c1b.
RSP: 002b:00007ffd677f8878 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f7c7f141c45
RDX: 00000000000000e7 RSI: ffffffffffffffd8 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000001
R13: 00007f7c7f1db100 R14: 00007f7c7f1dd3a8 R15: 00007f7c7f1dd3c0
</TASK>
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000168
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: Oops: 0002 [#1] PREEMPT SMP KASAN PTI
CPU: 0 UID: 0 PID: 314 Comm: syz-executor116 Tainted: G B W syzkaller #0 ca18b34a931c0a5bfcb0703d5cd6c5f88dc9958b
Tainted: [B]=BAD_PAGE, [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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 fd 17 95 ff 48 8d bb 68 01 00 00 be 04 00 00 00 e8 bc 02 ee ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 68 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 0d
RSP: 0018:ffffc9000120fb28 EFLAGS: 00010246
RAX: ffff888121c8a600 RBX: 0000000000000000 RCX: ffff888121c8a600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000120fb38 R08: ffffffff88bbb947 R09: 1ffffffff1177728
R10: dffffc0000000000 R11: fffffbfff1177729 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000168 CR3: 00000000074aa000 CR4: 00000000003526b0
Call Trace:
<TASK>
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:1970
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+0x1e5/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:961
do_group_exit+0x21f/0x2f0 kernel/exit.c:1104
__do_sys_exit_group kernel/exit.c:1115 [inline]
__se_sys_exit_group kernel/exit.c:1113 [inline]
__x64_sys_exit_group+0x43/0x50 kernel/exit.c:1113
x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7c7f141c45
Code: Unable to access opcode bytes at 0x7f7c7f141c1b.
RSP: 002b:00007ffd677f8878 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f7c7f141c45
RDX: 00000000000000e7 RSI: ffffffffffffffd8 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000001
R13: 00007f7c7f1db100 R14: 00007f7c7f1dd3a8 R15: 00007f7c7f1dd3c0
</TASK>
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 fd 17 95 ff 48 8d bb 68 01 00 00 be 04 00 00 00 e8 bc 02 ee ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 68 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 0d
RSP: 0018:ffffc9000120fb28 EFLAGS: 00010246
RAX: ffff888121c8a600 RBX: 0000000000000000 RCX: ffff888121c8a600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000120fb38 R08: ffffffff88bbb947 R09: 1ffffffff1177728
R10: dffffc0000000000 R11: fffffbfff1177729 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000168 CR3: 00000000074aa000 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 fd 17 95 ff call 0xff951810
13: 48 8d bb 68 01 00 00 lea 0x168(%rbx),%rdi
1a: be 04 00 00 00 mov $0x4,%esi
1f: e8 bc 02 ee ff call 0xffee02e0
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: 0d .byte 0xd
Struck through repros no longer work on HEAD.