rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=2ee/1/0x4000000000000000 softirq=82531/82535 fqs=5250 (t=10502 jiffies g=149981 q=160) NMI backtrace for cpu 1 CPU: 1 PID: 12853 Comm: syz-executor.1 Not tainted 5.9.0-rc3-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+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 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+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline] RIP: 0010:lock_acquire+0x27b/0xae0 kernel/locking/lockdep.c:5009 Code: ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 04 07 00 00 48 83 3d e8 cb 5b 08 00 0f 84 5a 05 00 00 4c 89 ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 08 48 c7 RSP: 0018:ffffc90000da8c28 EFLAGS: 00000282 RAX: 1ffffffff136c789 RBX: ffff888028576580 RCX: ffffffff815a184b RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffffc90000da8d68 R08: 0000000000000000 R09: ffffffff8c5f4ab7 R10: fffffbfff18be956 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000282 call_timer_fn+0x12e/0x760 kernel/time/timer.c:1410 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x1f7/0xa91 kernel/softirq.c:298 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] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline] RIP: 0010:lock_acquire+0x27b/0xae0 kernel/locking/lockdep.c:5009 Code: ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 04 07 00 00 48 83 3d e8 cb 5b 08 00 0f 84 5a 05 00 00 4c 89 ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 08 48 c7 RSP: 0018:ffffc90001997bc0 EFLAGS: 00000282 RAX: 1ffffffff136c789 RBX: ffff888028576580 RCX: ffffffff815a184b RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffff8880a454f748 R08: 0000000000000000 R09: ffffffff8c5f49ef R10: fffffbfff18be93d R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000282 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] lockref_put_or_lock+0x14/0x80 lib/lockref.c:174 fast_dput fs/dcache.c:747 [inline] dput+0x4b9/0xbc0 fs/dcache.c:865 find_next_child fs/libfs.c:261 [inline] simple_recursive_removal+0x136/0x6b0 fs/libfs.c:276 debugfs_remove fs/debugfs/inode.c:725 [inline] debugfs_remove+0x59/0x80 fs/debugfs/inode.c:719 blk_mq_debugfs_unregister_hctx+0x34/0xa0 block/blk-mq-debugfs.c:892 blk_mq_exit_hw_queues block/blk-mq.c:2599 [inline] blk_mq_exit_queue+0x374/0x510 block/blk-mq.c:3252 blk_cleanup_queue+0x13b/0x1e0 block/blk-core.c:398 loop_remove drivers/block/loop.c:2193 [inline] loop_control_ioctl drivers/block/loop.c:2291 [inline] loop_control_ioctl+0x3e1/0x480 drivers/block/loop.c:2257 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f35d871fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000012440 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000004 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fff149b597f R14: 00007f35d87209c0 R15: 000000000118cf4c