rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=2b3/1/0x4000000000000000 softirq=170187/170188 fqs=2393 (detected by 1, t=10502 jiffies, g=295413, q=928) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2938 Comm: systemd-udevd Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_lockdep_current_cpu_online+0xf4/0x130 Code: 23 75 27 49 83 c6 78 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 09 65 61 00 49 f7 06 01 00 00 00 75 04 31 c0 eb 02 01 65 ff 0d 9b c2 93 7e 74 08 5b 41 5c 41 5e 41 5f c3 0f 1f 44 RSP: 0018:ffffc90000007a38 EFLAGS: 00000002 RAX: 1ffffffff1964376 RBX: ffffffff8cb21bb0 RCX: 0000000000010003 RDX: 0000000000000000 RSI: 0000000000010004 RDI: ffff8880b9a3a418 RBP: ffffc90000007af0 R08: dffffc0000000000 R09: fffffbfff1bfa646 R10: fffffbfff1bfa646 R11: 0000000000000000 R12: 0000000000000001 R13: 1ffff92000000f70 R14: ffffffff8cb21b40 R15: dffffc0000000000 FS: 00007fd62dbb48c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7d3e0cf004 CR3: 00000000149d0000 CR4: 00000000003506f0 DR0: 0000800000000002 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_sched_held+0x74/0x130 kernel/rcu/update.c:123 trace_lock_release+0x4f/0x150 include/trace/events/lock.h:58 lock_release+0x82/0x810 kernel/locking/lockdep.c:5651 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:390 [inline] advance_sched+0x68b/0x930 net/sched/sch_taprio.c:759 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline] RIP: 0010:lock_is_held_type+0x63/0x190 kernel/locking/lockdep.c:5679 Code: fd 00 00 00 65 4c 8b 2c 25 c0 6f 02 00 41 83 bd 5c 0a 00 00 00 0f 85 e6 00 00 00 41 89 f6 49 89 ff 48 c7 04 24 00 00 00 00 9c <8f> 04 24 4c 8b 24 24 fa 48 c7 c7 00 0c 6f 8a e8 79 11 00 00 65 ff RSP: 0018:ffffc90001b6f510 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000080000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb1d860 RBP: ffffc90001b6f5f0 R08: dffffc0000000000 R09: fffffbfff1bfa646 R10: fffffbfff1bfa646 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff888018b18000 R14: 00000000ffffffff R15: ffffffff8cb1d860 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x89/0x130 kernel/rcu/update.c:125 trace_lock_release+0x4f/0x150 include/trace/events/lock.h:58 lock_release+0x82/0x810 kernel/locking/lockdep.c:5651 rcu_read_unlock include/linux/rcupdate.h:721 [inline] lookup_mnt+0x2c7/0x2e0 fs/namespace.c:663 __traverse_mounts fs/namei.c:1338 [inline] traverse_mounts+0x235/0x690 fs/namei.c:1385 handle_mounts fs/namei.c:1494 [inline] step_into+0x1e0/0x1f90 fs/namei.c:1800 walk_component+0x33a/0x790 fs/namei.c:1976 link_path_walk+0x697/0xd00 path_lookupat+0xab/0x6c0 fs/namei.c:2448 filename_lookup+0x270/0x640 fs/namei.c:2478 user_path_at_empty+0x40/0x1a0 fs/namei.c:2801 user_path_at include/linux/namei.h:57 [inline] do_faccessat+0x43f/0x940 fs/open.c:421 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd62ca269c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe9993d498 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 0000564b7a13bd20 RCX: 00007fd62ca269c7 RDX: 00746e657665752f RSI: 0000000000000000 RDI: 00007ffe9993d4a0 RBP: 00007ffe9993d520 R08: 000000000000fc00 R09: 0000000000001010 R10: 0000000000000020 R11: 0000000000000246 R12: 0000564b786d5856 R13: 0000564b7a140cf0 R14: 00007ffe9993d4a0 R15: 0000564b7a12cde0 rcu: rcu_preempt kthread starved for 5467 jiffies! g295413 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:26576 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4969 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6250 schedule+0x12b/0x1f0 kernel/sched/core.c:6323 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1955 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2128 kthread+0x468/0x490 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 8950 Comm: syz-executor.5 Not tainted 5.15.0-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+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2597 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xbb2/0xda0 kernel/smp.c:969 Code: 83 e6 01 31 ff e8 be b7 0b 00 41 83 e7 01 49 bf 00 00 00 00 00 fc ff df 75 0e e8 99 b3 0b 00 eb 4c 0f 1f 80 00 00 00 00 f3 90 <42> 0f b6 04 3b 84 c0 75 11 41 f7 45 00 01 00 00 00 74 2b e8 76 b3 RSP: 0018:ffffc90002cef380 EFLAGS: 00000293 RAX: ffffffff817898ea RBX: 1ffff11017348315 RCX: ffff88801c3b5700 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002cef4c0 R08: ffffffff817898b2 R09: ffffffff843959c0 R10: 0000000000000009 R11: ffff88801c3b5700 R12: 0000000000000000 R13: ffff8880b9a418a8 R14: ffff8880b9b3a600 R15: dffffc0000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1112 [inline] text_poke_bp_batch+0x310/0x940 arch/x86/kernel/alternative.c:1297 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_disable_cpuslocked+0xcc/0x1b0 kernel/jump_label.c:207 static_key_disable+0x16/0x20 kernel/jump_label.c:215 tracepoint_remove_func kernel/tracepoint.c:417 [inline] tracepoint_probe_unregister+0x730/0x9c0 kernel/tracepoint.c:551 trace_event_reg+0x215/0x250 perf_trace_event_unreg+0xaf/0x220 kernel/trace/trace_event_perf.c:162 perf_trace_destroy+0x93/0xb0 kernel/trace/trace_event_perf.c:243 _free_event+0x874/0xe50 kernel/events/core.c:4982 put_event kernel/events/core.c:5076 [inline] perf_event_release_kernel+0x86f/0x900 kernel/events/core.c:5191 perf_release+0x37/0x40 kernel/events/core.c:5201 __fput+0x3fc/0x870 fs/file_table.c:280 task_work_run+0x146/0x1c0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0x705/0x24f0 kernel/exit.c:832 do_group_exit+0x168/0x2d0 kernel/exit.c:929 get_signal+0x16b0/0x2090 kernel/signal.c:2820 arch_do_signal_or_restart+0x9c/0x730 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x191/0x220 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:300 do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f7bf4075ae9 Code: Unable to access opcode bytes at RIP 0x7f7bf4075abf. RSP: 002b:00007f7bf15eb218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f7bf4188f68 RCX: 00007f7bf4075ae9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7bf4188f68 RBP: 00007f7bf4188f60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7bf4188f6c R13: 00007ffed1193a5f R14: 00007f7bf15eb300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 23 75 27 and 0x27(%rbp),%esi 3: 49 83 c6 78 add $0x78,%r14 7: 4c 89 f0 mov %r14,%rax a: 48 c1 e8 03 shr $0x3,%rax e: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 13: 74 08 je 0x1d 15: 4c 89 f7 mov %r14,%rdi 18: e8 09 65 61 00 callq 0x616526 1d: 49 f7 06 01 00 00 00 testq $0x1,(%r14) 24: 75 04 jne 0x2a 26: 31 c0 xor %eax,%eax 28: eb 02 jmp 0x2c * 2a: b0 01 mov $0x1,%al <-- trapping instruction 2c: 65 ff 0d 9b c2 93 7e decl %gs:0x7e93c29b(%rip) # 0x7e93c2ce 33: 74 08 je 0x3d 35: 5b pop %rbx 36: 41 5c pop %r12 38: 41 5e pop %r14 3a: 41 5f pop %r15 3c: c3 retq 3d: 0f .byte 0xf 3e: 1f (bad) 3f: 44 rex.R