syzbot


KASAN: null-ptr-deref Write in d_delete_notify

Status: moderation: reported on 2025/12/04 02:30
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+cc864ee4e028e41b567d@syzkaller.appspotmail.com
First crash: 57d, last: 57d

Sample crash report:
==================================================================
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+0x1f/0x60 fs/inode.c:529
Write of size 4 at addr 0000000000000200 by task syz.6.969/10547

CPU: 1 UID: 0 PID: 10547 Comm: syz.6.969 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_inc_return include/linux/atomic/atomic-instrumented.h:453 [inline]
 ihold+0x1f/0x60 fs/inode.c:529
 d_delete_notify+0x46/0x190 include/linux/fsnotify.h:374
 vfs_unlink+0x435/0x640 fs/namei.c:5384
 __do_sys_mq_unlink ipc/mqueue.c:969 [inline]
 __se_sys_mq_unlink+0x2b2/0x360 ipc/mqueue.c:944
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6ede38f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6edc5b4038 EFLAGS: 00000246 ORIG_RAX: 00000000000000f1
RAX: ffffffffffffffda RBX: 00007f6ede5e6180 RCX: 00007f6ede38f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007f6ede413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6ede5e6218 R14: 00007f6ede5e6180 R15: 00007ffdc96a7d68
 </TASK>
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/30 02:19 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: null-ptr-deref Write in d_delete_notify
* Struck through repros no longer work on HEAD.