WARNING in fanotify_handle_event

Status: upstream: reported C repro on 2025/09/02 05:01
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+8efdc8e70c042d84d068@syzkaller.appspotmail.com
First crash: 325d, last: 53d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/09/04 upstream (ToT) 08b06c30a445 C [report] WARNING in fanotify_handle_event
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in fanotify_handle_event (2) exfat -1 C error 31 29d 619d 0/29 upstream: reported C repro on 2024/11/12 04:21
linux-5.15 WARNING in fanotify_handle_event origin:upstream -1 C error 4 33d 380d 0/3 upstream: reported C repro on 2025/07/08 09:14
linux-6.1 WARNING in fanotify_handle_event origin:upstream -1 C error 5 209d 380d 0/3 upstream: reported C repro on 2025/07/08 10:20
upstream WARNING in fanotify_handle_event fs -1 C done 5 2593d 2592d 12/29 fixed on 2019/07/10 21:40
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/01/21 13:13 4m bisect fix linux-6.6.y error job log
2025/12/19 11:41 1h59m bisect fix linux-6.6.y OK (0) job log log
2025/11/16 01:43 1h51m bisect fix linux-6.6.y OK (0) job log log
2025/10/11 13:57 1h43m bisect fix linux-6.6.y OK (0) job log log

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5933 at fs/notify/fanotify/fanotify.h:216 fanotify_info_copy_name fs/notify/fanotify/fanotify.h:216 [inline]
WARNING: CPU: 1 PID: 5933 at fs/notify/fanotify/fanotify.h:216 fanotify_alloc_name_event fs/notify/fanotify/fanotify.c:656 [inline]
WARNING: CPU: 1 PID: 5933 at fs/notify/fanotify/fanotify.h:216 fanotify_alloc_event fs/notify/fanotify/fanotify.c:820 [inline]
WARNING: CPU: 1 PID: 5933 at fs/notify/fanotify/fanotify.h:216 fanotify_handle_event+0x2411/0x3770 fs/notify/fanotify/fanotify.c:958
Modules linked in:
CPU: 1 PID: 5933 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:fanotify_info_copy_name fs/notify/fanotify/fanotify.h:216 [inline]
RIP: 0010:fanotify_alloc_name_event fs/notify/fanotify/fanotify.c:656 [inline]
RIP: 0010:fanotify_alloc_event fs/notify/fanotify/fanotify.c:820 [inline]
RIP: 0010:fanotify_handle_event+0x2411/0x3770 fs/notify/fanotify/fanotify.c:958
Code: f9 ff ff e8 51 a6 85 ff 0f 0b 49 bf 00 00 00 00 00 fc ff df e9 9c fa ff ff e8 3b a6 85 ff 0f 0b e9 98 fb ff ff e8 2f a6 85 ff <0f> 0b e9 1d fd ff ff e8 23 a6 85 ff 0f 0b e9 bd fe ff ff e8 17 a6
RSP: 0018:ffffc9000483f2a0 EFLAGS: 00010293
RAX: ffffffff820185c1 RBX: ffff88807acdc038 RCX: ffff8880273f8000
RDX: 0000000000000000 RSI: 0000000000000ffd RDI: 00000000000000ff
RBP: ffffc9000483f480 R08: 0000000000000002 R09: 0000000000000000
R10: ffff88807acdc038 R11: ffffed100f59b808 R12: ffff88807acdc000
R13: 0000000000000ffd R14: ffff88807acdc000 R15: dffffc0000000000
FS:  0000555573585500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001400 CR3: 0000000026149000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 send_to_group fs/notify/fsnotify.c:381 [inline]
 fsnotify+0x10ed/0x17c0 fs/notify/fsnotify.c:591
 __fsnotify_parent+0x655/0x7c0 fs/notify/fsnotify.c:248
 fsnotify_parent include/linux/fsnotify.h:77 [inline]
 fsnotify_file include/linux/fsnotify.h:107 [inline]
 fsnotify_open include/linux/fsnotify.h:338 [inline]
 do_dentry_open+0x1051/0x1500 fs/open.c:985
 do_open fs/namei.c:3640 [inline]
 path_openat+0x27f1/0x3230 fs/namei.c:3797
 do_filp_open+0x1f5/0x430 fs/namei.c:3824
 do_open_execat+0x14c/0x410 fs/exec.c:924
 bprm_execve+0x567/0x1700 fs/exec.c:1867
 do_execveat_common+0x51b/0x6c0 fs/exec.c:1998
 do_execve fs/exec.c:2072 [inline]
 __do_sys_execve fs/exec.c:2148 [inline]
 __se_sys_execve fs/exec.c:2143 [inline]
 __x64_sys_execve+0x92/0xa0 fs/exec.c:2143
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f44f879ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe65e0ed58 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007f44f8a15fa0 RCX: 00007f44f879ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000440
RBP: 00007f44f8832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44f8a15fac R14: 00007f44f8a15fa0 R15: 00007f44f8a15fa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/31 14:49 linux-6.6.y 0a40c6fbd105 6b4a8443 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in fanotify_handle_event
2026/05/31 13:09 linux-6.6.y 0a40c6fbd105 6b4a8443 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in fanotify_handle_event
2025/09/02 05:00 linux-6.6.y cc1a1c5b404a 807a3b61 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in fanotify_handle_event
* Struck through repros no longer work on HEAD.