rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=1da/1/0x4000000000000002 softirq=11279/11279 fqs=40 (t=10502 jiffies g=6557 q=181) rcu: rcu_preempt kthread starved for 10423 jiffies! g6557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 8138 Comm: rsyslogd Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:mod_memcg_page_state+0x168/0x190 include/linux/memcontrol.h:655 Code: c7 28 96 0a 89 e8 a8 9e 69 00 48 83 3d c8 21 c2 07 00 74 2d e8 99 27 2e 00 4c 89 ff 57 9d 0f 1f 44 00 00 5b 41 5c 41 5e 41 5f <5d> c3 e8 81 27 2e 00 0f 0b e8 7a 27 2e 00 0f 0b e8 73 27 2e 00 0f RSP: 0018:ffffc90001a37a50 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487433 RBX: ffff88808fb46808 RCX: ffff8880a500a100 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00028b6540 RBP: ffffc90001a37a50 R08: 000000000003a768 R09: ffffed1012eb231f R10: ffffed1012eb231f R11: 0000000000000000 R12: ffff88808fb468a0 R13: dffffc0000000000 R14: 1ffff11011f68d14 R15: ffff8880975918e8 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 do_syslog+0xdc7/0x1740 kernel/printk/printk.c:1525 kmsg_read+0x94/0xd0 fs/proc/kmsg.c:40 proc_reg_read+0x1e2/0x2d0 fs/proc/inode.c:223 __vfs_read+0xb8/0x730 fs/read_write.c:425 vfs_read+0x1dd/0x420 fs/read_write.c:461 ksys_read+0x117/0x220 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:595 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3792d2b1fd Code: d1 20 00 00 75 10 b8 00 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 5e fa ff ff 48 89 04 24 b8 00 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 a7 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f37902cae30 EFLAGS: 00000293 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00000000024cb650 RCX: 00007f3792d2b1fd RDX: 0000000000000fff RSI: 00007f3791aff5a0 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00000000024b6260 R09: 0000000000000000 R10: 203a7463656a626f R11: 0000000000000293 R12: 000000000065e420 R13: 00007f37902cb9c0 R14: 00007f3793370040 R15: 0000000000000003