rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=4b1/1/0x4000000000000000 softirq=53112/53114 fqs=1 (detected by 0, t=10506 jiffies, g=76265, q=159) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17720 Comm: syz-executor.0 Not tainted 5.18.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__this_cpu_preempt_check+0xd/0x20 lib/smp_processor_id.c:66 Code: 00 00 48 c7 c6 a0 a5 26 8a 48 c7 c7 e0 a5 26 8a e9 78 fe ff ff 0f 1f 84 00 00 00 00 00 55 48 89 fd 0f 1f 44 00 00 48 89 ee 5d <48> c7 c7 20 a6 26 8a e9 57 fe ff ff cc cc cc cc cc cc cc eb 1e 0f RSP: 0018:ffffc900003f8cf0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffffffffffffff RCX: ffffc900003f8d48 RDX: 1ffff1100eed0182 RSI: ffffffff89cc46e0 RDI: ffffffff89cc46e0 RBP: 1ffff9200007f1a1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000001 R14: ffff888077680c18 R15: ffff8880776801c0 FS: 00007f370e7e4700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020146000 CR3: 0000000040ebb000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000003b DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline] lock_release+0x3bb/0x720 kernel/locking/lockdep.c:5663 __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:389 [inline] advance_sched+0x435/0x9a0 net/sched/sch_taprio.c:764 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x609/0xe50 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:645 RIP: 0010:finish_task_switch.isra.0+0x323/0xb80 kernel/sched/core.c:4953 Code: a3 1e 1c 08 85 c0 75 02 0f 0b 48 85 db 0f 85 25 01 00 00 4c 89 f7 e8 fc f7 ff ff e8 27 c9 2d 00 fb 65 48 8b 1c 25 00 70 02 00 <48> 8d bb 80 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc900038f7af0 EFLAGS: 00000202 RAX: 0000000000002f0b RBX: ffff8880776801c0 RCX: 1ffffffff1b71799 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900038f7b38 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817ebe88 R11: 0000000000000001 R12: ffff8880b9d3add8 R13: ffff88801852e080 R14: ffff8880b9d3a080 R15: ffff8880b9d3aab8 context_switch kernel/sched/core.c:5076 [inline] __schedule+0xaa2/0x4cc0 kernel/sched/core.c:6388 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6553 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:399 [inline] snd_rawmidi_write+0x471/0xb90 sound/core/rawmidi.c:1541 vfs_write+0x269/0xac0 fs/read_write.c:589 ksys_write+0x1e8/0x250 fs/read_write.c:644 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: 0033:0x7f370d6890e9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f370e7e4168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f370d79bf60 RCX: 00007f370d6890e9 RDX: 00000000fffffd2c RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00007f370d6e308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd6aa814df R14: 00007f370e7e4300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10500 jiffies! g76265 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:28368 pid: 16 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5073 [inline] __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6388 schedule+0xd2/0x1f0 kernel/sched/core.c:6460 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1884 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2144 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 45 Comm: kworker/u4:2 Not tainted 5.18.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate 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:111 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:490 print_other_cpu_stall kernel/rcu/tree_stall.h:595 [inline] check_cpu_stall kernel/rcu/tree_stall.h:741 [inline] rcu_pending kernel/rcu/tree.c:3923 [inline] rcu_sched_clock_irq+0x1f7c/0x2150 kernel/rcu/tree.c:2625 update_process_times+0x16d/0x200 kernel/time/timer.c:1788 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243 tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1473 __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:645 RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:200 Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 70 02 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 a4 15 00 00 85 c0 74 2b 8b 82 80 15 00 00 <83> f8 02 75 20 48 8b 8a 88 15 00 00 8b 92 84 15 00 00 48 8b 01 48 RSP: 0018:ffffc90000d6f948 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff8880b9d3f7a0 RCX: 0000000000000000 RDX: ffff888016c70180 RSI: ffffffff816ca537 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816ca55d R11: 0000000000000000 R12: ffffed10173a7ef5 R13: 0000000000000001 R14: 0000000000000001 R15: dffffc0000000000 rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:411 [inline] smp_call_function_many_cond+0x497/0x1110 kernel/smp.c:969 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1184 [inline] text_poke_bp_batch+0x22c/0x6b0 arch/x86/kernel/alternative.c:1372 text_poke_flush arch/x86/kernel/alternative.c:1542 [inline] text_poke_flush arch/x86/kernel/alternative.c:1539 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1549 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0x32f/0x410 kernel/jump_label.c:830 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:774 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:766 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 c7 c6 a0 a5 26 8a mov $0xffffffff8a26a5a0,%rsi 9: 48 c7 c7 e0 a5 26 8a mov $0xffffffff8a26a5e0,%rdi 10: e9 78 fe ff ff jmpq 0xfffffe8d 15: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 1c: 00 1d: 55 push %rbp 1e: 48 89 fd mov %rdi,%rbp 21: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 26: 48 89 ee mov %rbp,%rsi 29: 5d pop %rbp * 2a: 48 c7 c7 20 a6 26 8a mov $0xffffffff8a26a620,%rdi <-- trapping instruction 31: e9 57 fe ff ff jmpq 0xfffffe8d 36: cc int3 37: cc int3 38: cc int3 39: cc int3 3a: cc int3 3b: cc int3 3c: cc int3 3d: eb 1e jmp 0x5d 3f: 0f .byte 0xf