[syzbot] [kernel?] WARNING: still has locks held in genl_rcv

[syzbot <syzbot+8c7d2de77ff6cd317568@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    903c1cf6dff9 Add linux-next specific files for 20260821
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14c09549580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=aa9dec010c9e69a7
dashboard link: https://syzkaller.appspot.com/bug?extid=8c7d2de77ff6cd317568
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e353f3c58611/disk-903c1cf6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c40cf34459f/vmlinux-903c1cf6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f2ffb2610fa7/bzImage-903c1cf6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8c7d2de77ff6cd317568@syzkaller.appspotmail.com

faux_driver regulatory: loading /lib/firmware/regulatory.db failed with error -4
faux_driver regulatory: Direct firmware load for regulatory.db failed with error -4
faux_driver regulatory: Falling back to sysfs fallback for: regulatory.db
====================================
WARNING: syz.1.698/9760 still has locks held!
syzkaller #0 Tainted: G             L     
------------------------------------
locks held by syz.1.698/9760: 1, last CPU#1:
 #0: ffffffff902c1228 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217

stack backtrace:
CPU: 1 UID: 0 PID: 9760 Comm: syz.1.698 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_held_locks_bug+0x82/0x90 kernel/locking/lockdep.c:6814
 try_to_freeze include/linux/freezer.h:62 [inline]
 usermodehelper_read_trylock+0x207/0x2c0 kernel/umh.c:228
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:157 [inline]
 firmware_fallback_sysfs+0x16e/0xa50 drivers/base/firmware_loader/fallback.c:248
 _request_firmware+0x1049/0x1780 drivers/base/firmware_loader/main.c:898
 request_firmware+0x36/0x50 drivers/base/firmware_loader/main.c:948
 reg_reload_regdb+0x95/0x490 net/wireless/reg.c:1067
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2713
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
 __sys_sendmsg net/socket.c:2799 [inline]
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f3639e0d9
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:00007f7f345b4028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7f36626180 RCX: 00007f7f3639e0d9
RDX: 0000000020000000 RSI: 00002000000001c0 RDI: 0000000000000005
RBP: 00007f7f36435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7f36626218 R14: 00007f7f36626180 R15: 00007fff90f25828
 </TASK>


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