[v6.6] INFO: task hung in genl_rcv_msg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1e89a1be4fe9 Linux 6.6.117
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15efce12580000
kernel config: https://syzkaller.appspot.com/x/.config?x=12606d4b8832c7e4
dashboard link: https://syzkaller.appspot.com/bug?extid=d46c0004fee0be3ef662
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0841ff5925b8/disk-1e89a1be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b5c591b98846/vmlinux-1e89a1be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c863ab0f2374/bzImage-1e89a1be.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d46c00...@syzkaller.appspotmail.com

INFO: task syz.2.60:6111 blocked for more than 156 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.60 state:D stack:24136 pid:6111 ppid:5831 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
genl_lock net/netlink/genetlink.c:33 [inline]
genl_op_lock net/netlink/genetlink.c:58 [inline]
genl_rcv_msg+0x10e/0x790 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
___sys_sendmsg+0x220/0x290 net/socket.c:2649
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2687 [inline]
__se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
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: 0033:0x7fc57758f749
RSP: 002b:00007fc5783a9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc5777e5fa0 RCX: 00007fc57758f749
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007fc577613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5777e6038 R14: 00007fc5777e5fa0 R15: 00007fff8ce87da8
</TASK>
INFO: task syz.1.62:6117 blocked for more than 166 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.62 state:D stack:26504 pid:6117 ppid:5829 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
genl_lock net/netlink/genetlink.c:33 [inline]
genl_op_lock net/netlink/genetlink.c:58 [inline]
genl_rcv_msg+0x10e/0x790 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346


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