syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4960/1:b..l P737/1:b..l
	(detected by 1, t=10502 jiffies, g=10677, q=231)
task:kworker/u4:5    state:R  running task     stack:    0 pid:  737 ppid:     2 flags:0x00000008
Workqueue: bat_events batadv_nc_worker
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6376
 preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6780
 arm64_preempt_schedule_irq+0x174/0x2c4 arch/arm64/kernel/entry-common.c:260
 el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:580
 check_kcov_mode kernel/kcov.c:163 [inline]
 write_comp_data kernel/kcov.c:218 [inline]
 __sanitizer_cov_trace_const_cmp4+0x5c/0xb0 kernel/kcov.c:284
 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
task:syz-executor.1  state:R  running task     stack:    0 pid: 4960 ppid:  3978 flags:0x00000004
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6376
 preempt_schedule_common+0x140/0x260 kernel/sched/core.c:6552
 preempt_schedule+0x64/0x84 kernel/sched/core.c:6577
 __local_bh_enable_ip+0x254/0x470 kernel/softirq.c:390
 local_bh_enable+0x28/0x1d0 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:809 [inline]
 ip_finish_output2+0xe78/0x131c net/ipv4/ip_output.c:229
 __ip_finish_output+0x1b0/0x458
 ip_finish_output+0x40/0x218 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0x330/0x49c net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0xe70/0x1930 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x5c/0x78 net/ipv4/ip_output.c:546
 __tcp_transmit_skb+0x1944/0x31e8 net/ipv4/tcp_output.c:1402
 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
 tcp_connect+0x19fc/0x3e34 net/ipv4/tcp_output.c:3889
 tcp_v4_connect+0xc48/0x15fc net/ipv4/tcp_ipv4.c:314
 __inet_stream_connect+0x204/0xc00 net/ipv4/af_inet.c:669
 inet_stream_connect+0x74/0xb0 net/ipv4/af_inet.c:733
 __sys_connect_file net/socket.c:1918 [inline]
 __sys_connect+0x268/0x290 net/socket.c:1935
 __do_sys_connect net/socket.c:1945 [inline]
 __se_sys_connect net/socket.c:1942 [inline]
 __arm64_sys_connect+0x7c/0x94 net/socket.c:1942
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
rcu: rcu_preempt kthread starved for 10508 jiffies! g10677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:    0 pid:   15 ppid:     2 flags:0x00000008
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6376
 schedule+0x11c/0x1c8 kernel/sched/core.c:6459
 schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x26c/0x13d4 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xc4/0x2c4 kernel/rcu/tree.c:2145
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 0:
task:syz-executor.2  state:R  running task     stack:    0 pid: 4961 ppid:  4333 flags:0x00000001
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 0xffff0000d9801b40