syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5179/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=34917, q=191 ncpus=2)
task:kworker/u4:6    state:R  running task     stack:25640 pid:5179  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0xc9a/0x5880 kernel/sched/core.c:6669
 preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:6931
 preempt_schedule_notrace_thunk+0x1a/0x20 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x86/0xb0 kernel/rcu/tree.c:696
 rcu_read_unlock include/linux/rcupdate.h:802 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xb41/0xfe0 net/batman-adv/network-coding.c:719
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10509 jiffies! g34917 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=41715
rcu: rcu_preempt kthread starved for 10515 jiffies! g34917 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:28400 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0xc9a/0x5880 kernel/sched/core.c:6669
 schedule+0xde/0x1a0 kernel/sched/core.c:6745
 schedule_timeout+0x14e/0x2b0 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x190/0x910 kernel/rcu/tree.c:1609
 rcu_gp_kthread+0x23a/0x360 kernel/rcu/tree.c:1808
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 52 Comm: kworker/0:1H Not tainted 6.4.0-rc4-syzkaller-00276-ge5282a7d8f6b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Workqueue: events_highpri snd_vmidi_output_work
RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline]
RIP: 0010:write_comp_data+0xf/0x90 kernel/kcov.c:236
Code: 65 48 8b 04 25 c0 bb 03 00 48 8b 80 00 16 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 65 8b 05 b1 7a 7f 7e 49 89 f1 89 c6 49 89 d2 <81> e6 00 01 00 00 49 89 f8 65 48 8b 14 25 c0 bb 03 00 a9 00 01 ff
RSP: 0018:ffffc90000007618 EFLAGS: 00000246
RAX: 0000000000000302 RBX: ffff888088727980 RCX: ffffffff883f0a5f
RDX: 0000000000000001 RSI: 0000000000000302 RDI: 0000000000000001
RBP: ffff88802c228000 R08: ffff888088727980 R09: 0000000000000000
R10: 0000000000000001 R11: 0200000000000000 R12: dffffc0000000000
R13: 0000000000000001 R14: ffff88802c2282f0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020c43000 CR3: 000000007d77f000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 __list_del_entry include/linux/list.h:134 [inline]
 list_move_tail include/linux/list.h:229 [inline]
 fq_pie_qdisc_dequeue+0x66f/0x9c0 net/sched/sch_fq_pie.c:248
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x1b2/0x1780 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3868 [inline]
 __dev_queue_xmit+0x2215/0x3b10 net/core/dev.c:4210
 dev_queue_xmit include/linux/netdevice.h:3085 [inline]
 neigh_connected_output+0x3c2/0x550 net/core/neighbour.c:1581
 neigh_output include/net/neighbour.h:544 [inline]
 ip6_finish_output2+0x55a/0x1560 net/ipv6/ip6_output.c:134
 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
 ip6_finish_output+0x69a/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:292 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:458 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 ndisc_send_skb+0xa63/0x1850 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x132/0x6f0 net/ipv6/ndisc.c:718
 addrconf_rs_timer+0x3f1/0x870 net/ipv6/addrconf.c:3936
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700
 expire_timers+0x29b/0x4b0 kernel/time/timer.c:1751
 __run_timers kernel/time/timer.c:2022 [inline]
 __run_timers kernel/time/timer.c:1995 [inline]
 run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
 __do_softirq+0x1d4/0x905 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x3c/0x70 kernel/locking/spinlock.c:194
Code: 74 24 10 e8 36 8f 52 f7 48 89 ef e8 5e fd 52 f7 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 <e8> cf d2 44 f7 65 8b 05 d0 62 f0 75 85 c0 74 0a 5b 5d c3 e8 bc 88
RSP: 0018:ffffc90000bd7c18 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff22b60be
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff88802717f630 R08: 0000000000000001 R09: ffffffff91528e6f
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000293
R13: 0000000000001000 R14: ffff88802717f630 R15: ffff88802717f600
 spin_unlock_irqrestore include/linux/spinlock.h:405 [inline]
 snd_rawmidi_proceed+0xf7/0x140 sound/core/rawmidi.c:1500
 snd_vmidi_output_work+0x30a/0x390 sound/core/seq/seq_virmidi.c:139
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>