rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=ad3/1/0x4000000000000000 softirq=10920/10921 fqs=2 (detected by 0, t=10505 jiffies, g=11917, q=337) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3545 Comm: udevd Not tainted 5.15.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:91 [inline] RIP: 0010:lock_acquire+0x128/0x4f0 kernel/locking/lockdep.c:5599 Code: 3d 80 dc 86 0c 00 0f 84 3f 01 00 00 65 8b 05 2f bb 9f 7e 85 c0 0f 85 88 01 00 00 65 48 8b 1d df b1 9f 7e 48 81 c3 ec 0a 00 00 <48> 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 c4 02 00 00 83 3b RSP: 0018:ffffc90000dd0ac0 EFLAGS: 00000086 RAX: 0000000000000000 RBX: ffff88807d02c66c RCX: ffffffff8162bd8c RDX: 0000000000000000 RSI: ffffffff8ad904e0 RDI: ffffffff8ad904a0 RBP: ffffc90000dd0c08 R08: dffffc0000000000 R09: fffffbfff1bd2cd6 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920001ba160 R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f965249dc80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd9b6c4d58 CR3: 0000000020d7f000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 debug_object_activate+0x63/0x4e0 lib/debugobjects.c:694 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:475 [inline] enqueue_hrtimer+0x30/0x390 kernel/time/hrtimer.c:1084 __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0x6b6/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627 Code: 2b 00 74 08 4c 89 f7 e8 4c 8c 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90002d67400 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920005ace8c RCX: 1ffff920005ace2c RDX: dffffc0000000000 RSI: ffffffff8a8b3d20 RDI: ffffffff8ad90500 RBP: ffffc90002d67548 R08: dffffc0000000000 R09: fffffbfff20ec621 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005ace88 R13: dffffc0000000000 R14: ffffc90002d67460 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] dput+0x35/0x1a0 fs/dcache.c:879 step_into+0x352/0xe90 fs/namei.c:1815 walk_component+0x359/0x610 fs/namei.c:1982 link_path_walk+0x642/0xd90 path_openat+0x249/0x2f20 fs/namei.c:3738 do_filp_open+0x21c/0x460 fs/namei.c:3769 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1280 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f96525cc477 Code: 10 00 00 00 44 8b 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 44 89 c2 4c 89 ce bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 82 69 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fff52988dd8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000561daf5b3170 RCX: 00007f96525cc477 RDX: 0000000000090800 RSI: 0000561daf5a1470 RDI: 00000000ffffff9c RBP: 0000561daf5d6810 R08: 0000000000090800 R09: 0000561daf5a1470 R10: 0000000000000000 R11: 0000000000000287 R12: 0000561daf5a1470 R13: 00000000000000fe R14: 0000561d7953e1c4 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10495 jiffies! g11917 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27096 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 4174 Comm: syz-executor Not tainted 5.15.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969 Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 4c d5 0b 00 41 83 e7 01 75 07 e8 e1 d1 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc90002e07b80 EFLAGS: 00000293 RAX: ffffffff8174a1f4 RBX: 1ffff110172280b1 RCX: ffff88802aec5940 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002e07cb8 R08: ffffffff8174a1c4 R09: fffffbfff20ec636 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001 R13: ffff8880b9140588 R14: ffff8880b903b380 R15: 0000000000000001 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 invalidate_bdev+0x8a/0xb0 block/bdev.c:86 ext4_put_super+0x8e9/0x1060 fs/ext4/super.c:1255 generic_shutdown_super+0x130/0x310 fs/super.c:475 kill_block_super+0x7a/0xe0 fs/super.c:1427 deactivate_locked_super+0xa0/0x110 fs/super.c:335 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143 task_work_run+0x129/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fe515a76a47 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffd9b6c5508 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fe515ae84b4 RCX: 00007fe515a76a47 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd9b6c55c0 RBP: 00007ffd9b6c55c0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd9b6c6640 R13: 00007fe515ae84b4 R14: 00000000000142d3 R15: 00007ffd9b6c6680 vkms_vblank_simulate: vblank timer overrun