syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4092/1:b..l
	(detected by 1, t=10502 jiffies, g=4957, q=71)
task:syz.2.12        state:R  running task     stack:    0 pid: 4092 ppid:  3973 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
 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+0x28/0x34 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:809 [inline]
 ip6_finish_output2+0x13e8/0x1c4c net/ipv6/ip6_output.c:127
 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197
 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x270/0x594 net/ipv6/ip6_output.c:230
 dst_output include/net/dst.h:443 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip6_xmit+0x1070/0x1a60 net/ipv6/ip6_output.c:330
 inet6_csk_xmit+0x3b8/0x61c net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x1944/0x31e8 net/ipv4/tcp_output.c:1402
 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
 tcp_write_xmit+0x12bc/0x4dc0 net/ipv4/tcp_output.c:2705
 __tcp_push_pending_frames+0x98/0x228 net/ipv4/tcp_output.c:2890
 tcp_push_pending_frames include/net/tcp.h:1915 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:5493 [inline]
 tcp_rcv_established+0xe7c/0x1f40 net/ipv4/tcp_input.c:5904
 tcp_v6_do_rcv+0x434/0x1360 net/ipv6/tcp_ipv6.c:1526
 sk_backlog_rcv include/net/sock.h:1059 [inline]
 __release_sock+0x1a8/0x408 net/core/sock.c:2724
 release_sock+0x68/0x270 net/core/sock.c:3265
 tcp_sendpage+0xc0/0xdc net/ipv4/tcp.c:1145
 inet_sendpage+0x190/0x2f4 net/ipv4/af_inet.c:842
 kernel_sendpage+0x24c/0x300 net/socket.c:3534
 sock_sendpage+0x88/0xcc net/socket.c:1025
 pipe_to_sendpage+0x1fc/0x2d4 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x2c8/0x7d8 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x168/0x1fc fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe4/0x1c0 fs/splice.c:936
 splice_direct_to_actor+0x408/0x9a0 fs/splice.c:891
 do_splice_direct+0x1f4/0x334 fs/splice.c:979
 do_sendfile+0x4bc/0xc70 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __arm64_sys_sendfile64+0x160/0x408 fs/read_write.c:1303
 __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 10367 jiffies! g4957 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:    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
 preempt_schedule_common+0x140/0x260 kernel/sched/core.c:6552
 preempt_schedule+0x64/0x84 kernel/sched/core.c:6577
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x114/0x158 kernel/locking/spinlock.c:194
 __debug_object_init+0x218/0xbec lib/debugobjects.c:632
 debug_object_init_on_stack+0x20/0x2c lib/debugobjects.c:671
 init_timer_on_stack_key kernel/time/timer.c:752 [inline]
 schedule_timeout+0x12c/0x344 kernel/time/timer.c:1912
 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 1:
task:syz.4.5         state:R  running task     stack:    0 pid: 4100 ppid:  3982 flags:0x00000000
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 sched_show_task+0x43c/0x574 kernel/sched/core.c:8640
 dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10914
 rcu_check_gp_kthread_starvation+0x1f0/0x254 kernel/rcu/tree_stall.h:488
 print_other_cpu_stall+0x202c/0x2290 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0x1894/0x1b8c kernel/rcu/tree.c:2619
 update_process_times+0x1d4/0x270 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1686 [inline]
 __hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x2c0/0xb64 kernel/time/hrtimer.c:1812
 timer_handler drivers/clocksource/arm_arch_timer.c:659 [inline]
 arch_timer_handler_virt+0x74/0x88 drivers/clocksource/arm_arch_timer.c:670
 handle_percpu_devid_irq+0x29c/0x7fc kernel/irq/chip.c:933
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq_desc kernel/irq/irqdesc.c:651 [inline]
 handle_domain_irq+0xec/0x178 kernel/irq/irqdesc.c:706
 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:758
 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899
 do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267
 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
 write_comp_data kernel/kcov.c:240 [inline]
 __sanitizer_cov_trace_const_cmp4+0xa4/0xb0 kernel/kcov.c:284
 task_tgid_vnr include/linux/sched.h:1587 [inline]
 __arm64_sys_getpid+0x20/0x30 kernel/sys.c:945
 __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