rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=5ee/1/0x4000000000000000 softirq=225608/225609 fqs=1 (t=10500 jiffies g=398281 q=285) rcu: rcu_preempt kthread timer wakeup didn't happen for 10497 jiffies! g398281 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=135927 rcu: rcu_preempt kthread starved for 10498 jiffies! g398281 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:28864 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 schedule+0xd3/0x270 kernel/sched/core.c:6017 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline] rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169 kthread+0x3e5/0x4d0 kernel/kthread.c:319 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: 27607 Comm: syz-executor.1 Not tainted 5.14.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:queued_write_lock_slowpath+0x137/0x2c0 kernel/locking/qrwlock.c:78 Code: 00 00 00 00 fc ff df 49 01 c7 41 83 c6 03 41 0f b6 07 41 38 c6 7c 08 84 c0 0f 85 3e 01 00 00 8b 03 3d 00 01 00 00 74 19 f3 90 <41> 0f b6 07 41 38 c6 7c ec 84 c0 74 e8 48 89 df e8 d4 3e 60 00 eb RSP: 0018:ffffc900131e7a38 EFLAGS: 00000006 RAX: 0000000000000300 RBX: ffffffff8b60a080 RCX: ffffffff815ba45f RDX: fffffbfff16c1411 RSI: 0000000000000004 RDI: ffffffff8b60a080 RBP: 1ffff9200263cf48 R08: 0000000000000001 R09: ffffffff8b60a083 R10: fffffbfff16c1410 R11: 0000000000000000 R12: ffffffff8b60a084 R13: 00000000000000ff R14: 0000000000000003 R15: fffffbfff16c1410 FS: 0000000002fd8400(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f91f3551718 CR3: 000000016970c000 CR4: 0000000000350ee0 Call Trace: queued_write_lock include/asm-generic/qrwlock.h:97 [inline] do_raw_write_lock+0x1ce/0x280 kernel/locking/spinlock_debug.c:207 copy_process+0x360e/0x74d0 kernel/fork.c:2238 kernel_clone+0xe7/0xac0 kernel/fork.c:2509 __do_sys_clone+0xc8/0x110 kernel/fork.c:2626 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x467a11 Code: 48 85 ff 74 3d 48 85 f6 74 38 48 83 ee 10 48 89 4e 08 48 89 3e 48 89 d7 4c 89 c2 4d 89 c8 4c 8b 54 24 08 b8 38 00 00 00 0f 05 <48> 85 c0 7c 13 74 01 c3 31 ed 58 5f ff d0 48 89 c7 b8 3c 00 00 00 RSP: 002b:00007ffdef361558 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f91f3551700 RCX: 0000000000467a11 RDX: 00007f91f35519d0 RSI: 00007f91f35512f0 RDI: 00000000003d0f00 RBP: 00007ffdef361790 R08: 00007f91f3551700 R09: 00007f91f3551700 R10: 00007f91f35519d0 R11: 0000000000000206 R12: 00007ffdef36160e R13: 00007ffdef36160f R14: 00007f91f3551300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 29903 Comm: syz-executor.4 Not tainted 5.14.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:700 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x9f/0x747 kernel/rcu/tree.c:2641 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:199 Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 4e fa 2d f8 48 89 ef e8 f6 6f 2e f8 e8 c1 aa 4e f8 fb bf 01 00 00 00 c6 4d 22 f8 65 8b 05 af c8 d4 76 85 c0 74 02 5d c3 e8 cb 1d d3 RSP: 0018:ffffc90000007e08 EFLAGS: 00000202 RAX: 0000000001ce9038 RBX: ffffffff8735a730 RCX: 1ffffffff1f9b862 RDX: 0000000000000000 RSI: 0000000000000102 RDI: 0000000000000001 RBP: ffff8880b9c40280 R08: 0000000000000001 R09: ffffffff8fcd48f7 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90000007e98 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880b9c40280 expire_timers kernel/time/timer.c:1465 [inline] __run_timers.part.0+0x665/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:197 Code: ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 65 8b 05 f9 46 8c 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 f0 01 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc90009727b58 EFLAGS: 00000283 RAX: 0000000080000001 RBX: 0000000000000000 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff81458c03 RDI: 0000000000000003 RBP: ffffc90009727d1c R08: 0000000000000020 R09: ffffffff8b60a083 R10: ffffffff81458bf4 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000040000000 R15: ffff88814e7cb880 wait_consider_task+0x3a3/0x3b80 kernel/exit.c:1358 do_wait_thread kernel/exit.c:1397 [inline] do_wait+0x6ca/0xce0 kernel/exit.c:1514 kernel_wait4+0x14c/0x260 kernel/exit.c:1677 __do_sys_wait4+0x13f/0x150 kernel/exit.c:1705 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x464a87 Code: 89 7c 24 10 48 89 4c 24 18 e8 d5 44 02 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 05 45 02 00 8b 44 RSP: 002b:00007ffce147a900 EFLAGS: 00000293 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 0000000000000b2d RCX: 0000000000464a87 RDX: 0000000040000001 RSI: 00007ffce147a99c RDI: 00000000ffffffff RBP: 00007ffce147a99c R08: 0000000000000000 R09: 00007ffce15b7080 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032 R13: 000000000022aa12 R14: 0000000000000005 R15: 00007ffce147aa00 ---------------- Code disassembly (best guess), 6 bytes skipped: 0: df 49 01 fisttps 0x1(%rcx) 3: c7 41 83 c6 03 41 0f movl $0xf4103c6,-0x7d(%rcx) a: b6 07 mov $0x7,%dh c: 41 38 c6 cmp %al,%r14b f: 7c 08 jl 0x19 11: 84 c0 test %al,%al 13: 0f 85 3e 01 00 00 jne 0x157 19: 8b 03 mov (%rbx),%eax 1b: 3d 00 01 00 00 cmp $0x100,%eax 20: 74 19 je 0x3b 22: f3 90 pause 24: 41 0f b6 07 movzbl (%r15),%eax <-- trapping instruction 28: 41 38 c6 cmp %al,%r14b 2b: 7c ec jl 0x19 2d: 84 c0 test %al,%al 2f: 74 e8 je 0x19 31: 48 89 df mov %rbx,%rdi 34: e8 d4 3e 60 00 callq 0x603f0d 39: eb .byte 0xeb