[v6.6] WARNING in kernfs_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f5b4c104b7d Linux 6.6.95
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1646508c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b80883c3ded77c16
dashboard link: https://syzkaller.appspot.com/bug?extid=9fff6b476ec89fe103eb
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0efd4e01816e/disk-3f5b4c10.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f7c9d20858cc/vmlinux-3f5b4c10.xz
kernel image: https://storage.googleapis.com/syzbot-assets/18f8dc74ef68/bzImage-3f5b4c10.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9fff6b...@syzkaller.appspotmail.com

usb 3-1: Direct firmware load for ueagle-atm/eagleII.fw failed with error -2
usb 3-1: Falling back to sysfs fallback for: ueagle-atm/eagleII.fw
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5926 at fs/kernfs/dir.c:526 kernfs_get+0x6c/0x90 fs/kernfs/dir.c:526
Modules linked in:
CPU: 0 PID: 5926 Comm: kworker/0:13 Not tainted 6.6.95-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events request_firmware_work_func
RIP: 0010:kernfs_get+0x6c/0x90 fs/kernfs/dir.c:526
Code: 72 ff 85 ed 74 1f e8 33 54 72 ff 48 89 df be 04 00 00 00 e8 e6 04 cb ff f0 ff 03 eb 05 e8 1c 54 72 ff 5b 5d c3 e8 14 54 72 ff <0f> 0b eb dd 89 d9 80 e1 07 80 c1 03 38 c1 7c bd 48 89 df e8 bc 02
RSP: 0018:ffffc90004f27740 EFLAGS: 00010293
RAX: ffffffff8213424c RBX: ffff88802de7a6c8 RCX: ffff88807b191e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802de7a6cb R09: 1ffff11005bcf4d9
R10: dffffc0000000000 R11: ffffed1005bcf4da R12: ffff88805d205e28
R13: 1ffff1100ba40bc6 R14: ffff88805d205e30 R15: ffff88805d205e18
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c39606d CR3: 0000000061bf3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
sysfs_get include/linux/sysfs.h:651 [inline]
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x74b/0xc70 lib/kobject.c:240
kobject_add_varg lib/kobject.c:374 [inline]
kobject_add+0x156/0x220 lib/kobject.c:426
class_dir_create_and_add drivers/base/core.c:3226 [inline]
get_device_parent+0x316/0x390 drivers/base/core.c:3277
device_add+0x2e1/0xc20 drivers/base/core.c:3607
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:82 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
firmware_fallback_sysfs+0x2e9/0x940 drivers/base/firmware_loader/fallback.c:234
_request_firmware+0xed9/0x1510 drivers/base/firmware_loader/main.c:936
request_firmware_work_func+0xb0/0x1b0 drivers/base/firmware_loader/main.c:1189
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.