[v6.6] WARNING in kernfs_new_node (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0a40c6fbd105 Linux 6.6.141
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=134452b6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=90249d2d52c08134
dashboard link: https://syzkaller.appspot.com/bug?extid=a58c0d611f6dab088a7a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f48d56604601/disk-0a40c6fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cf126fb7ea87/vmlinux-0a40c6fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8a5aa7959b43/bzImage-0a40c6fb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a58c0d...@syzkaller.appspotmail.com

usb 2-1: Direct firmware load for ueagle-atm/eagleI.fw failed with error -2
usb 2-1: Falling back to sysfs fallback for: ueagle-atm/eagleI.fw
------------[ cut here ]------------
WARNING: CPU: 0 PID: 787 at fs/kernfs/dir.c:526 kernfs_get fs/kernfs/dir.c:526 [inline]
WARNING: CPU: 0 PID: 787 at fs/kernfs/dir.c:526 kernfs_new_node+0x1f9/0x260 fs/kernfs/dir.c:703
Modules linked in:
CPU: 0 PID: 787 Comm: kworker/0:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events request_firmware_work_func
RIP: 0010:kernfs_get fs/kernfs/dir.c:526 [inline]
RIP: 0010:kernfs_new_node+0x1f9/0x260 fs/kernfs/dir.c:703
Code: ff df 80 3c 08 00 74 08 4c 89 ff e8 81 4b ca ff 49 89 1f 4c 89 f0 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 77 0b 72 ff <0f> 0b eb 9e 89 e9 80 e1 07 fe c1 38 c1 0f 8c 45 fe ff ff 48 89 ef
RSP: 0018:ffffc90003b17618 EFLAGS: 00010293
RAX: ffffffff82152079 RBX: ffff88806ba8c3e0 RCX: ffff88802133bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88806ba8c3e3 R09: 1ffff1100d75187c
R10: dffffc0000000000 R11: ffffed100d75187d R12: 00000000000041ed
R13: 0000000000000000 R14: ffff888066576aa8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ecb57e08d CR3: 0000000019ad2000 CR4: 00000000003506f0
Call Trace:
<TASK>
kernfs_create_dir_ns+0x44/0x120 fs/kernfs/dir.c:1061
sysfs_create_dir_ns+0x130/0x2a0 fs/sysfs/dir.c:59
create_dir lib/kobject.c:73 [inline]
kobject_add_internal+0x61c/0xcc0 lib/kobject.c:240
kobject_add_varg lib/kobject.c:374 [inline]
kobject_add+0x164/0x240 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+0x2e1/0xc50 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+0x2e9/0x930 drivers/base/firmware_loader/fallback.c:234
_request_firmware+0xf27/0x1510 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:2653 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
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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