[v6.6] WARNING in fanotify_handle_event

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc1a1c5b404a Linux 6.6.103
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10030e62580000
kernel config: https://syzkaller.appspot.com/x/.config?x=412020841cf033b0
dashboard link: https://syzkaller.appspot.com/bug?extid=8efdc8e70c042d84d068
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14030e62580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13150312580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46c06862a545/disk-cc1a1c5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/38ddabb6fc8b/vmlinux-cc1a1c5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b130b7d031b5/bzImage-cc1a1c5b.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/347d09d2865d/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=13b94a42580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8efdc8...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5947 at fs/notify/fanotify/fanotify.h:216 fanotify_info_copy_name fs/notify/fanotify/fanotify.h:216 [inline]
WARNING: CPU: 0 PID: 5947 at fs/notify/fanotify/fanotify.h:216 fanotify_alloc_name_event fs/notify/fanotify/fanotify.c:656 [inline]
WARNING: CPU: 0 PID: 5947 at fs/notify/fanotify/fanotify.h:216 fanotify_alloc_event fs/notify/fanotify/fanotify.c:820 [inline]
WARNING: CPU: 0 PID: 5947 at fs/notify/fanotify/fanotify.h:216 fanotify_handle_event+0x2458/0x3750 fs/notify/fanotify/fanotify.c:958
Modules linked in:
CPU: 0 PID: 5947 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
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+0x2458/0x3750 fs/notify/fanotify/fanotify.c:958
Code: f9 ff ff e8 fa 0f 87 ff 0f 0b 49 bf 00 00 00 00 00 fc ff df e9 92 fa ff ff e8 e4 0f 87 ff 0f 0b e9 88 fb ff ff e8 d8 0f 87 ff <0f> 0b e9 10 fd ff ff e8 cc 0f 87 ff 0f 0b e9 bc fe ff ff e8 c0 0f
RSP: 0018:ffffc900032872e0 EFLAGS: 00010293
RAX: ffffffff81fe7fc8 RBX: ffff88802bcc0038 RCX: ffff888022563c00
RDX: 0000000000000000 RSI: 0000000000000ffd RDI: 00000000000000ff
RBP: ffffc900032874c0 R08: 0000000000000002 R09: 0000000000000000
R10: ffff88802bcc0038 R11: ffffed1005798008 R12: ffff88802bcc0000
R13: 0000000000000ffd R14: ffff88802bcc0000 R15: dffffc0000000000
FS: 000055558ed8c500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001400 CR3: 00000000766df000 CR4: 00000000003506f0
Call Trace:
<TASK>
send_to_group fs/notify/fsnotify.c:374 [inline]
fsnotify+0x10c8/0x1780 fs/notify/fsnotify.c:584
__fsnotify_parent+0x5e6/0x720 fs/notify/fsnotify.c:241
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:3632 [inline]
path_openat+0x274b/0x3190 fs/namei.c:3789
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_open_execat+0x133/0x3d0 fs/exec.c:924
bprm_execve+0x567/0x16f0 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:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4a7e58ebe9
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:00007ffce4863168 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007f4a7e7c5fa0 RCX: 00007f4a7e58ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000440
RBP: 00007f4a7e611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4a7e7c5fa0 R14: 00007f4a7e7c5fa0 R15: 0000000000000003
</TASK>


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