rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=4a6/1/0x4000000000000000 softirq=33026/33026 fqs=0 (detected by 1, t=10502 jiffies, g=55257, q=100) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6889 Comm: syz-executor.1 Not tainted 5.9.0-rc4-next-20200909-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] RIP: 0010:hlock_class kernel/locking/lockdep.c:179 [inline] RIP: 0010:__lock_acquire+0x1361/0x55d0 kernel/locking/lockdep.c:4792 Code: ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 5f 32 00 00 0f b7 5d f8 66 81 e3 ff 1f 0f b7 db be 08 00 00 00 48 89 d8 48 c1 f8 06 <48> 8d 3c c5 e0 b9 9b 8c e8 92 00 5a 00 48 0f a3 1d ca c6 42 0b 0f RSP: 0018:ffffc90000007aa0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000057 RCX: ffffffff8158ef64 RDX: 1ffff1100ca18d7d RSI: 0000000000000008 RDI: ffff8880650c6be8 RBP: ffff8880650c6bf0 R08: 0000000000000000 R09: ffffffff8c9bb9e7 R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880650c6240 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000001eff940(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001f08a98 CR3: 00000000650b6000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159 debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:636 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:480 [inline] enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:969 __run_hrtimer kernel/time/hrtimer.c:1541 [inline] __hrtimer_run_queues+0xb54/0xea0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x13e/0x520 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __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] sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x20 kernel/kcov.c:284 Code: 84 00 00 00 00 00 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 cc fe ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 <89> f2 89 fe bf 05 00 00 00 e9 ae fe ff ff 0f 1f 40 00 66 2e 0f 1f RSP: 0018:ffffc900055178e0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff83624fe7 RDX: ffff8880650c6240 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff8880a8877580 R08: 0000000000000001 R09: ffffffff8cf26ba7 R10: 0000000000000010 R11: 0000000000000000 R12: 0000000000000100 R13: 0000000000000295 R14: dffffc0000000000 R15: 0000000000000000 tomoyo_domain_quota_is_ok+0x307/0x550 security/tomoyo/util.c:1071 tomoyo_supervisor+0x2d4/0xeb0 security/tomoyo/common.c:2089 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline] tomoyo_path_permission security/tomoyo/file.c:587 [inline] tomoyo_path_permission+0x25c/0x360 security/tomoyo/file.c:573 tomoyo_path_perm+0x2e7/0x3f0 security/tomoyo/file.c:838 tomoyo_path_unlink+0x8e/0xd0 security/tomoyo/tomoyo.c:150 security_path_unlink+0xd7/0x150 security/security.c:1100 do_unlinkat+0x375/0x660 fs/namei.c:3894 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d307 Code: 00 66 90 b8 58 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 dd b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffcaf019ba8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045d307 RDX: 00007ffcaf019bc0 RSI: 00007ffcaf019bc0 RDI: 00007ffcaf019c50 RBP: 00000000000002b9 R08: 0000000000000000 R09: 0000000000000010 R10: 000000000000000a R11: 0000000000000246 R12: 00007ffcaf01ace0 R13: 0000000001f00a60 R14: 0000000000000000 R15: 00007ffcaf01ace0 rcu: rcu_preempt kthread starved for 10502 jiffies! g55257 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:28856 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3777 [inline] __schedule+0xea5/0x21b0 kernel/sched/core.c:4526 schedule+0xcf/0x270 kernel/sched/core.c:4604 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1931 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2105 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294