rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=466/1/0x4000000000000000 softirq=193924/193924 fqs=9 (t=10500 jiffies g=360357 q=151) rcu: rcu_preempt kthread starved for 10403 jiffies! g360357 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29120 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x148/0x250 kernel/time/timer.c:1897 rcu_gp_fqs_loop kernel/rcu/tree.c:1874 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2044 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 NMI backtrace for cpu 0 CPU: 0 PID: 12732 Comm: syz-executor.5 Not tainted 5.8.0-rc4-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:320 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline] check_cpu_stall kernel/rcu/tree_stall.h:627 [inline] rcu_pending kernel/rcu/tree.c:3489 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccc kernel/rcu/tree.c:2504 update_process_times+0x25/0x60 kernel/time/timer.c:1726 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x108/0x290 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4f/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:1093 Code: 00 00 ff ff ff 3f 7f 02 5b c3 0f 0b 5b c3 e8 07 64 52 00 eb b3 e8 00 64 52 00 eb e0 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 <53> 48 83 ec 08 65 ff 05 d4 54 a1 7e e8 0f fe 83 06 48 c7 c3 00 6c RSP: 0018:ffffc90000007d18 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8163a89e RDX: ffff8880216e8180 RSI: ffffffff8163a9b8 RDI: 0000000000000001 RBP: 0000000000000100 R08: 0000000000000000 R09: ffffffff8aae5b0f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 1ffff92000000fa9 R15: dffffc0000000000 rcu_read_lock_held_common kernel/rcu/update.c:118 [inline] rcu_read_lock_sched_held+0x1c/0xb0 kernel/rcu/update.c:133 trace_timer_expire_exit include/trace/events/timer.h:125 [inline] call_timer_fn+0x67d/0x760 kernel/time/timer.c:1405 expire_timers kernel/time/timer.c:1449 [inline] __run_timers.part.0+0x54c/0xa20 kernel/time/timer.c:1773 __run_timers kernel/time/timer.c:1745 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1786 __do_softirq+0x34c/0xa60 kernel/softirq.c:292 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x111/0x170 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:387 [inline] __irq_exit_rcu kernel/softirq.c:417 [inline] irq_exit_rcu+0x229/0x270 kernel/softirq.c:429 sysvec_apic_timer_interrupt+0x54/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587 RIP: 0010:tomoyo_check_acl+0xad/0x410 security/tomoyo/domain.c:173 Code: 03 00 00 49 8b 1c 24 49 39 dc 0f 84 f5 01 00 00 e8 e8 c2 12 fe 48 8d 7b 18 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 0f b6 04 28 <38> d0 7f 08 84 c0 0f 85 d7 02 00 00 44 0f b6 73 18 31 ff 44 89 f6 RSP: 0018:ffffc90008c07758 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888095f0c680 RCX: ffffc90013ba5000 RDX: 0000000000000000 RSI: ffffffff8360f478 RDI: ffff888095f0c698 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888095033a10 R13: ffffc90008c07848 R14: 0000000000000000 R15: 0000000000000000 tomoyo_path_permission security/tomoyo/file.c:586 [inline] tomoyo_path_permission+0x1f5/0x360 security/tomoyo/file.c:573 tomoyo_check_open_permission+0x33e/0x380 security/tomoyo/file.c:777 tomoyo_file_open security/tomoyo/tomoyo.c:313 [inline] tomoyo_file_open+0xa3/0xd0 security/tomoyo/tomoyo.c:308 security_file_open+0x52/0x3f0 security/security.c:1574 do_dentry_open+0x3a0/0x1290 fs/open.c:815 do_open fs/namei.c:3243 [inline] path_openat+0x1bb9/0x2750 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] __do_sys_openat fs/open.c:1209 [inline] __se_sys_openat fs/open.c:1204 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1204 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cba9 Code: Bad RIP value. RSP: 002b:00007f9692defc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004fa360 RCX: 000000000045cba9 RDX: 0000000000000000 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000824 R14: 00000000004cb22d R15: 00007f9692df06d4