[v6.1] BUG: soft lockup in sys_sendmmsg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d2869ace6eeb Linux 6.1.31
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1229c1d1280000
kernel config: https://syzkaller.appspot.com/x/.config?x=11263f470b7a4c92
dashboard link: https://syzkaller.appspot.com/bug?extid=ba2b722fc35aab8d1041
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b17a7cd87498/disk-d2869ace.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cc8291ae723a/vmlinux-d2869ace.xz
kernel image: https://storage.googleapis.com/syzbot-assets/04943541fc25/Image-d2869ace.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ba2b72...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [syz-executor.4:8952]
Modules linked in:
irq event stamp: 4615
hardirqs last enabled at (4614): [<ffff8000120fb1c0>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline]
hardirqs last enabled at (4614): [<ffff8000120fb1c0>] exit_to_kernel_mode+0xe8/0x118 arch/arm64/kernel/entry-common.c:94
hardirqs last disabled at (4615): [<ffff8000120f8e9c>] __el1_irq arch/arm64/kernel/entry-common.c:468 [inline]
hardirqs last disabled at (4615): [<ffff8000120f8e9c>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:486
softirqs last enabled at (210): [<ffff800010809308>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (220): [<ffff800010f10808>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
CPU: 1 PID: 8952 Comm: syz-executor.4 Not tainted 6.1.31-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __sanitizer_cov_trace_pc+0x80/0x8c kernel/kcov.c:225
lr : __list_del_entry include/linux/list.h:137 [inline]
lr : list_move_tail include/linux/list.h:229 [inline]
lr : fq_pie_qdisc_dequeue+0x290/0x8ac net/sched/sch_fq_pie.c:248
sp : ffff80001fba6830
x29: ffff80001fba68b0 x28: ffff000131c21010 x27: ffff0000dabf1ae8
x26: ffff0000dabf1af0 x25: dfff800000000000 x24: ffff0000dabf1ae0
x23: ffff000131c21000 x22: 0000000000000040 x21: 1fffe00026384200
x20: 0000000000000000 x19: 0000000000000000 x18: ffff80001fba6500
x17: ffff800010f0d250 x16: ffff8000084fa384 x15: 0000000000000000
x14: 0000000000000002 x13: 0000000000000001 x12: 0000000000040000
x11: 000000000003ffff x10: ffff800023b8b000 x9 : ffff80001071078c
x8 : 0000000000040000 x7 : ffff80000840686c x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : ffff000131c21010 x1 : 0000000000000000 x0 : 0000000000000001
Call trace:
__sanitizer_cov_trace_pc+0x80/0x8c kernel/kcov.c:223
dequeue_skb net/sched/sch_generic.c:292 [inline]
qdisc_restart net/sched/sch_generic.c:397 [inline]
__qdisc_run+0x204/0x239c net/sched/sch_generic.c:415
__dev_xmit_skb net/core/dev.c:3885 [inline]
__dev_queue_xmit+0xe14/0x38d8 net/core/dev.c:4227
dev_queue_xmit include/linux/netdevice.h:3018 [inline]
neigh_connected_output+0x2f8/0x38c net/core/neighbour.c:1612
neigh_output include/net/neighbour.h:546 [inline]
ip6_finish_output2+0xdb4/0x1a98 net/ipv6/ip6_output.c:134
ip6_fragment+0x1b7c/0x2a88 net/ipv6/ip6_output.c:946
__ip6_finish_output net/ipv6/ip6_output.c:193 [inline]
ip6_finish_output+0x518/0x8c8 net/ipv6/ip6_output.c:206
NF_HOOK_COND include/linux/netfilter.h:291 [inline]
ip6_output+0x270/0x594 net/ipv6/ip6_output.c:227
dst_output include/net/dst.h:444 [inline]
ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161
ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1989
udp_v6_send_skb+0x9fc/0x1780 net/ipv6/udp.c:1292
udpv6_sendmsg+0x19c4/0x28a4 net/ipv6/udp.c:1586
inet6_sendmsg+0xb4/0xd8 net/ipv6/af_inet6.c:667
sock_sendmsg_nosec net/socket.c:716 [inline]
sock_sendmsg net/socket.c:736 [inline]
____sys_sendmsg+0x558/0x844 net/socket.c:2482
___sys_sendmsg net/socket.c:2536 [inline]
__sys_sendmmsg+0x318/0x7d8 net/socket.c:2622
__do_sys_sendmmsg net/socket.c:2651 [inline]
__se_sys_sendmmsg net/socket.c:2648 [inline]
__arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2648
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581


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[syzbot]

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