rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=741/1/0x4000000000000002 softirq=26830/26831 fqs=22 (detected by 1, t=10502 jiffies, g=36689, q=263) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10706 Comm: syz.4.1348 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216 Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 44 4e 89 7e 65 8b RSP: 0018:ffffc90000007258 EFLAGS: 00000046 RAX: ffffffff8197f01b RBX: ffffc90000007400 RCX: ffff88805797bb80 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000007350 R08: ffffc900000073d7 R09: ffffc900000073a0 R10: dffffc0000000000 R11: fffff52000000e7b R12: dffffc0000000000 R13: ffffc90000007406 R14: 0000000000000000 R15: ffffc900000075c0 FS: 00007f8cb523e6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdc7d8ce10 CR3: 00000000649b1000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: perf_prepare_sample+0x127b/0x1cd0 kernel/events/core.c:7750 __perf_event_output kernel/events/core.c:7802 [inline] perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 12 f2 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc900000079e0 EFLAGS: 00000206 RAX: 421e3f8832b68f00 RBX: 1ffff92000000f40 RCX: 421e3f8832b68f00 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc90000007ac0 R08: ffffffff901d41bf R09: 1ffffffff203a837 R10: dffffc0000000000 R11: fffffbfff203a838 R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:410 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x53e/0x800 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x339/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:alloc_fd+0xe1/0x630 fs/file.c:488 Code: 07 89 c3 31 ff 89 c6 e8 5d e7 a8 ff 85 db 74 25 48 8b 7c 24 20 be ff ff ff ff e8 0a 2e ec 07 89 c3 31 ff 89 c6 e8 3f e7 a8 ff <85> db 74 0e e8 d6 e3 a8 ff eb 24 e8 cf e3 a8 ff eb 1d e8 68 df 93 RSP: 0018:ffffc900032cfd28 EFLAGS: 00000293 RAX: ffffffff81d03d31 RBX: 0000000000000001 RCX: ffff88805797bb80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000659f94 R12: dffffc0000000000 R13: ffff88802b3171c0 R14: ffff88806006e780 R15: 0000000000000002 __do_sys_perf_event_open kernel/events/core.c:12463 [inline] __se_sys_perf_event_open+0x493/0x1bb0 kernel/events/core.c:12387 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8cb6fe4819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8cb523e028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f8cb725dfa0 RCX: 00007f8cb6fe4819 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00002000000003c0 RBP: 00007f8cb707ac91 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8cb725e038 R14: 00007f8cb725dfa0 R15: 00007ffef56e94c8 rcu: rcu_preempt kthread starved for 10458 jiffies! g36689 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:26992 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 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 1 CPU: 1 PID: 10702 Comm: syz.4.1348 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x843/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 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:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:918 Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 77 b3 4a 00 44 38 e3 75 10 66 90 0f 00 2d 99 e2 f3 08 fb f4 16 ff ff ff fb e9 10 ff ff ff e8 47 cf 87 08 89 f9 80 e1 07 38 RSP: 0018:ffffc90002ebfb40 EFLAGS: 00000246 RAX: 58e66bb63c2bc400 RBX: 0000000000000003 RCX: 58e66bb63c2bc400 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc90002ebfbf0 R08: ffffffff901d40df R09: 1ffffffff203a81b R10: dffffc0000000000 R11: fffffbfff203a81c R12: 0000000000000003 R13: ffff8880b913b154 R14: dffffc0000000000 R15: 1ffff920005d7f68 pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:364 [inline] pick_file+0x2e/0x220 fs/file.c:623 __range_close fs/file.c:689 [inline] __close_range+0x214/0x510 fs/file.c:747 __do_sys_close_range fs/open.c:1410 [inline] __se_sys_close_range fs/open.c:1407 [inline] __x64_sys_close_range+0x76/0x80 fs/open.c:1407 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8cb6fe4819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffef56e9628 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: ffffffffffffffda RBX: 00007f8cb725fda0 RCX: 00007f8cb6fe4819 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f8cb725fda0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007f8cb725fcb0 R11: 0000000000000246 R12: 0000000000059b73 R13: 00007f8cb725e18c R14: 0000000000059910 R15: 00007f8cb725e180