[v5.15] BUG: soft lockup in wg_packet_handshake_send_worker

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d98fd109f827 Linux 5.15.172
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=172fd130580000
kernel config: https://syzkaller.appspot.com/x/.config?x=59de8684d8fa887b
dashboard link: https://syzkaller.appspot.com/bug?extid=92d358f9ab4bd8a4863c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f084f6e552b3/disk-d98fd109.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0a4045cbebf6/vmlinux-d98fd109.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d65ebe028930/Image-d98fd109.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+92d358...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#1 stuck for 21s! [kworker/u4:0:9]
Modules linked in:
irq event stamp: 1107351
hardirqs last enabled at (1107350): [<ffff800011ab9be4>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:81 [inline]
hardirqs last enabled at (1107350): [<ffff800011ab9be4>] exit_to_kernel_mode+0x100/0x178 arch/arm64/kernel/entry-common.c:91
hardirqs last disabled at (1107351): [<ffff800011ab9e2c>] enter_el1_irq_or_nmi+0x10/0x1c arch/arm64/kernel/entry-common.c:227
softirqs last enabled at (1102748): [<ffff80000c83fe34>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:31
softirqs last disabled at (1102752): [<ffff80000c84af2c>] wg_socket_send_skb_to_peer+0x64/0x1a8 drivers/net/wireguard/socket.c:173
CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted 5.15.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : fq_dequeue+0x5a4/0x18fc net/sched/sch_fq.c:561
lr : fq_dequeue+0x578/0x18fc net/sched/sch_fq.c:551
sp : ffff80001bc37000
x29: ffff80001bc37120 x28: 1fffe0001a3aec08 x27: 0000003bb0f19a78
x26: dfff800000000000 x25: ffff0000d1d76000 x24: ffff0000e37f42e8
x23: 1fffe0001a3aec09 x22: ffff0000d1d76040 x21: ffff0000e37f42d0
x20: 1fffe0001c6fe85a x19: ffff0000d1d76048 x18: 0000000000000802
x17: 0000000000000000 x16: ffff8000082ec8b8 x15: 0000000000000001
x14: 1ffff0000295806a x13: dfff800000000000 x12: 0000000000000003
x11: 0000000000000802 x10: 0000000000000000 x9 : ffff0000c0948000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff80000804605c
x2 : 0000000000000002 x1 : 00000000f5060902 x0 : 0000000000000001
Call trace:
fq_dequeue+0x5a4/0x18fc net/sched/sch_fq.c:561
dequeue_skb net/sched/sch_generic.c:292 [inline]
qdisc_restart net/sched/sch_generic.c:397 [inline]
__qdisc_run+0x1ec/0x1fc0 net/sched/sch_generic.c:415
__dev_xmit_skb net/core/dev.c:3910 [inline]
__dev_queue_xmit+0x1038/0x2ac8 net/core/dev.c:4221
dev_queue_xmit+0x24/0x34 net/core/dev.c:4289
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0x132c/0x1cec net/ipv6/ip6_output.c:130
__ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:201
ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:211
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip6_output+0x274/0x594 net/ipv6/ip6_output.c:234
dst_output include/net/dst.h:443 [inline]
ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161
ip6tunnel_xmit include/net/ip6_tunnel.h:160 [inline]
udp_tunnel6_xmit_skb+0x43c/0x938 net/ipv6/ip6_udp_tunnel.c:109
send6+0x560/0x930 drivers/net/wireguard/socket.c:152
wg_socket_send_skb_to_peer+0xfc/0x1a8 drivers/net/wireguard/socket.c:178
wg_socket_send_buffer_to_peer+0xec/0x144 drivers/net/wireguard/socket.c:200
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x1a8/0x2a4 drivers/net/wireguard/send.c:51
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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