rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=2ee/1/0x4000000000000004 softirq=35534/35536 fqs=5215 rcu: (t=10500 jiffies g=24297 q=458) NMI backtrace for cpu 1 CPU: 1 PID: 4740 Comm: syz-executor.0 Not tainted 4.19.154-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+0x123/0x177 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.4+0x3e/0x76 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xe6/0x11a lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1340 print_cpu_stall kernel/rcu/tree.c:1478 [inline] check_cpu_stall kernel/rcu/tree.c:1550 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold.81+0x5cc/0xd67 kernel/rcu/tree.c:2682 update_process_times+0x28/0x90 kernel/time/timer.c:1650 tick_sched_handle+0x77/0x140 kernel/time/tick-sched.c:168 tick_sched_timer+0x37/0xf0 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1401 [inline] __hrtimer_run_queues+0x2f7/0xab0 kernel/time/hrtimer.c:1463 hrtimer_interrupt+0x2df/0x760 kernel/time/hrtimer.c:1521 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline] smp_apic_timer_interrupt+0x114/0x540 arch/x86/kernel/apic/apic.c:1092 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] RIP: 0010:do_raw_spin_lock+0x43/0x240 kernel/locking/spinlock_debug.c:112 Code: 83 c7 04 48 89 fa 48 83 ec 08 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 bb 01 00 00 8b 43 04 <3d> ad 4e ad de 0f 85 5e 01 00 00 4c 8d 6b 10 48 b8 00 00 00 00 00 RSP: 0018:ffff8880ba707c50 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 00000000dead4ead RBX: ffff888066ebe128 RCX: 1ffff1100cf5bdbc RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888066ebe12c RBP: ffff8880ba707c78 R08: 00000000000070e2 R09: 0000000000000003 R10: ffff888067adedc0 R11: 0000000000000001 R12: ffff8880a04bca80 R13: ffff8880ba707dc0 R14: ffff888066ebe330 R15: ffff888066ebe128 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_lock+0x35/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] pie_timer+0x8e/0x670 net/sched/sch_pie.c:433 call_timer_fn+0x14c/0x510 kernel/time/timer.c:1338 expire_timers kernel/time/timer.c:1375 [inline] __run_timers kernel/time/timer.c:1703 [inline] run_timer_softirq+0xb63/0x1180 kernel/time/timer.c:1716 __do_softirq+0x260/0x92d kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:544 [inline] smp_apic_timer_interrupt+0x13e/0x540 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_release+0x44e/0x850 kernel/locking/lockdep.c:3929 Code: 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f8 02 00 00 48 83 3d 69 55 c5 06 00 0f 84 49 02 00 00 48 8b bd 68 ff ff ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 c7 04 03 00 00 00 RSP: 0018:ffff8880617f7718 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 1ffff1100c2feee7 RCX: 1ffff1100cf5bdb2 RDX: 1ffffffff1023ff1 RSI: 0000000000000000 RDI: 0000000000000282 RBP: ffff8880617f77c0 R08: 0000000000004861 R09: 0000000000000001 R10: ffff888067aded70 R11: 0000000000000001 R12: ffff888067ade4c0 R13: 0000000000000002 R14: 0000000000000000 R15: ffff888067ade4c0 rcu_lock_release include/linux/rcupdate.h:247 [inline] rcu_read_unlock include/linux/rcupdate.h:681 [inline] mntput_no_expire+0x24d/0x760 fs/namespace.c:1154 mntput fs/namespace.c:1187 [inline] drop_mountpoint+0x80/0xa0 fs/namespace.c:174 pin_kill+0x140/0x640 fs/fs_pin.c:50 group_pin_kill+0x44/0x120 fs/fs_pin.c:101 namespace_unlock+0xe0/0xf0 fs/namespace.c:1365 drop_collected_mounts+0x7d/0x90 fs/namespace.c:1799 put_mnt_ns+0x42/0x60 fs/namespace.c:3248 free_nsproxy+0x37/0x1a0 kernel/nsproxy.c:176 switch_task_namespaces+0x91/0xb0 kernel/nsproxy.c:229 exit_task_namespaces+0xb/0x10 kernel/nsproxy.c:234 do_exit+0xa65/0x2d20 kernel/exit.c:886 do_group_exit+0xf4/0x2f0 kernel/exit.c:990 get_signal+0x313/0x1a30 kernel/signal.c:2588 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a89 Code: Bad RIP value. RSP: 002b:00007f369cb20c78 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: 0000000000000006 RBX: 0000000000000005 RCX: 0000000000459a89 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 000000002001d000 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 00007f369cb216d4 R13: 00000000004c68d5 R14: 00000000004dbae8 R15: 00000000ffffffff