rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=efd/1/0x4000000000000000 softirq=69401/69402 fqs=0 (t=10500 jiffies g=112793 q=97) rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g112793 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=62530 rcu: rcu_preempt kthread starved for 10500 jiffies! g112793 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 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: 1498 Comm: syz-executor.2 Not tainted 5.15.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:clockevents_program_event+0x79/0x370 kernel/time/clockevents.c:315 Code: 38 4c 89 65 18 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 95 02 00 00 44 8b 6d 38 01 00 00 00 44 89 ee e8 6a 2c 0d 00 41 83 fd 01 0f 84 00 02 00 RSP: 0018:ffffc90000dc0ed8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff110173a3e67 RSI: ffffffff8168d8fd RDI: ffff8880b9d1f338 RBP: ffff8880b9d1f300 R08: 0000000000000000 R09: ffff8880b9d223c3 R10: ffffffff8168d8ef R11: 0000000000000000 R12: 000000d9018b6cb4 R13: 0000000000000003 R14: 0000000000000000 R15: ffff8880b9d223c0 FS: 00007f7d8b1b3700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00d1f47e0 CR3: 00000000333e8000 CR4: 0000000000350ee0 Call Trace: tick_program_event+0xac/0x140 kernel/time/tick-oneshot.c:44 hrtimer_interrupt+0x36e/0x790 kernel/time/hrtimer.c:1824 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:__schedule+0x948/0x26f0 kernel/sched/core.c:6166 Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 cb 17 00 00 4c 89 ef 4d 89 7c 24 10 4c 89 fe e8 40 b2 c9 f7 48 89 c7 e8 68 66 19 f8 <48> 8b 8d 38 ff ff ff 48 b8 00 00 00 00 00 fc ff df 48 c7 04 01 00 RSP: 0018:ffffc9000424f7c0 EFLAGS: 00000202 RAX: 0000000000fa65f7 RBX: 0000000000000000 RCX: 1ffffffff1adc5d1 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000424f888 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817c2848 R11: 0000000000000000 R12: ffff8880b9d31a40 R13: ffff8880b9d32500 R14: 0000000000000001 R15: ffff88802d351c80 schedule+0xd3/0x270 kernel/sched/core.c:6366 tty_open+0x885/0x1000 drivers/tty/tty_io.c:2153 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11d0 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x1c9a/0x2740 fs/namei.c:3561 do_filp_open+0x1aa/0x400 fs/namei.c:3588 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227 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: 0033:0x7f7d8dc3c8d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7d8b1b3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f7d8dd40f60 RCX: 00007f7d8dc3c8d9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f7d8dc96cb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe30a542ef R14: 00007f7d8b1b3300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 1497 Comm: syz-executor.0 Not tainted 5.15.0-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:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 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:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2599 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:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 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:mutex_optimistic_spin kernel/locking/mutex.c:469 [inline] RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:599 [inline] RIP: 0010:__mutex_lock+0x3e4/0x12f0 kernel/locking/mutex.c:729 Code: 0f 85 27 0c 00 00 4d 39 e6 0f 84 35 0c 00 00 48 8b 84 24 90 00 00 00 48 89 c6 48 89 04 24 48 83 e6 f8 0f 84 1c 0c 00 00 31 c9 <31> d2 48 89 ef e8 f2 e7 22 f8 84 c0 0f 84 03 01 00 00 f3 90 be 08 RSP: 0018:ffffc9000435f748 EFLAGS: 00000246 RAX: fffffbfff1add1c1 RBX: ffff88802d351c80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88802d351c80 RDI: ffff88807da28158 RBP: ffff88807da28158 R08: 0000000000000000 R09: ffff88807da2815f R10: ffffed100fb4502b R11: 0000000000000000 R12: ffff88802d351c80 R13: ffffffff8d6e8e08 R14: ffff8880205dd580 R15: dffffc0000000000 tty_lock_interruptible+0xca/0x170 drivers/tty/tty_mutex.c:31 tty_open_by_driver drivers/tty/tty_io.c:2084 [inline] tty_open+0x9a6/0x1000 drivers/tty/tty_io.c:2146 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11d0 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x1c9a/0x2740 fs/namei.c:3561 do_filp_open+0x1aa/0x400 fs/namei.c:3588 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227 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: 0033:0x7f0940d388d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f093e2af188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0940e3cf60 RCX: 00007f0940d388d9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f0940d92cb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdb9b6a8af R14: 00007f093e2af300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 4c 89 65 18 mov %r12,0x18(%rbp) 4: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax b: fc ff df e: 48 89 fa mov %rdi,%rdx 11: 48 c1 ea 03 shr $0x3,%rdx 15: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 19: 84 c0 test %al,%al 1b: 74 08 je 0x25 1d: 3c 03 cmp $0x3,%al 1f: 0f 8e 95 02 00 00 jle 0x2ba 25: 44 8b 6d 38 mov 0x38(%rbp),%r13d * 29: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction 2e: 44 89 ee mov %r13d,%esi 31: e8 6a 2c 0d 00 callq 0xd2ca0 36: 41 83 fd 01 cmp $0x1,%r13d 3a: 0f .byte 0xf 3b: 84 00 test %al,(%rax) 3d: 02 00 add (%rax),%al