rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=78745, q=63) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295011423-4295000921), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g78745 f0x2 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: task:rcu_preempt state:R running task stack:28656 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2950 Comm: kworker/1:3 Not tainted 5.16.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events pwq_unbound_release_workfn RIP: 0010:lock_is_held_type+0x0/0x140 kernel/locking/lockdep.c:5665 Code: 48 c7 c6 a0 0f ac 89 48 c7 c7 20 0c ac 89 89 44 24 04 e8 1d 70 bc ff 0f 0b 8b 44 24 04 eb bd 66 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 41 56 41 55 41 bd ff ff ff ff 41 54 55 53 48 83 ec 08 8b 0d RSP: 0018:ffffc90000dc0df8 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff8880b9d2a500 RCX: 0000000000000000 RDX: 1ffffffff177194e RSI: 00000000ffffffff RDI: ffffffff8bb83be0 RBP: ffff888078b54b40 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff8166ea0c R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: ffff8880b9d2a400 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc97494ff8 CR3: 000000007253f000 CR4: 0000000000350ee0 Call Trace: lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_hrtimer_start include/trace/events/timer.h:195 [inline] debug_activate kernel/time/hrtimer.c:476 [inline] enqueue_hrtimer+0x2bd/0x3e0 kernel/time/hrtimer.c:1084 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xb02/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lockdep_unregister_key+0x1c9/0x250 kernel/locking/lockdep.c:6326 Code: 00 00 00 48 89 ee e8 46 fd ff ff 4c 89 f7 e8 5e c9 ff ff e8 09 cc ff ff 9c 58 f6 c4 02 75 26 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c 41 5d 41 5e 41 5f e9 19 24 08 00 0f 0b 5b 5d 41 5c 41 5d RSP: 0018:ffffc90001cefcb0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffff888093482498 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888092c0a128 R08: ffffffff8bb8ca00 R09: ffffffff9069ad0b R10: fffffbfff20d35a1 R11: 000000000000f2e3 R12: 0000000000000246 R13: 0000000000000000 R14: ffffffff8ff6a9b8 R15: ffffffff900f7838 wq_unregister_lockdep kernel/workqueue.c:3499 [inline] pwq_unbound_release_workfn+0x235/0x340 kernel/workqueue.c:3737 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 48 c7 c6 a0 0f ac 89 mov $0xffffffff89ac0fa0,%rsi 7: 48 c7 c7 20 0c ac 89 mov $0xffffffff89ac0c20,%rdi e: 89 44 24 04 mov %eax,0x4(%rsp) 12: e8 1d 70 bc ff callq 0xffbc7034 17: 0f 0b ud2 19: 8b 44 24 04 mov 0x4(%rsp),%eax 1d: eb bd jmp 0xffffffdc 1f: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 26: 00 00 00 00 * 2a: 41 57 push %r15 <-- trapping instruction 2c: 41 56 push %r14 2e: 41 55 push %r13 30: 41 bd ff ff ff ff mov $0xffffffff,%r13d 36: 41 54 push %r12 38: 55 push %rbp 39: 53 push %rbx 3a: 48 83 ec 08 sub $0x8,%rsp 3e: 8b .byte 0x8b 3f: 0d .byte 0xd