rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6776 rcu: (detected by 1, t=10503 jiffies, g=23793, q=3580 ncpus=2) task:udevd state:R running task stack:25032 pid:6776 ppid:5156 flags:0x0000400a Call Trace: sched_show_task+0x481/0x5a0 kernel/sched/core.c:9178 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline] print_other_cpu_stall+0xfa7/0x1340 kernel/rcu/tree_stall.h:637 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline] rcu_pending kernel/rcu/tree.c:3950 [inline] rcu_sched_clock_irq+0x87c/0x1220 kernel/rcu/tree.c:2295 update_process_times+0x147/0x1b0 kernel/time/timer.c:2071 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492 __run_hrtimer kernel/time/hrtimer.c:1755 [inline] __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1819 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:check_preemption_disabled+0x18/0x110 lib/smp_processor_id.c:14 Code: 20 66 fc 8a eb 0c 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 <65> 8b 05 8d 5c 96 75 65 8b 0d 82 5c 96 75 f7 c1 ff ff ff 7f 74 1f RSP: 0018:ffffc900001f0618 EFLAGS: 00000286 RAX: e675f0c1b7ea9900 RBX: 0000000000000000 RCX: ffff88802a02da00 RDX: ffff88802a02da00 RSI: ffffffff8afc6620 RDI: ffffffff8afc65e0 RBP: ffffc900001f0778 R08: ffffc900001f070f R09: 0000000000000000 R10: ffffc900001f0700 R11: fffff5200003e0e2 R12: ffffffff8cbfae10 R13: 1ffff9200003e0dc R14: ffff88802c13c200 R15: ffffc900001f0700 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:700 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_held+0x15/0x40 kernel/rcu/update.c:348 bpf_prog_run_array include/linux/bpf.h:1961 [inline] trace_call_bpf+0x1f1/0x690 kernel/trace/bpf_trace.c:143 perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10262 perf_trace_lock_acquire+0x32a/0x3e0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x3e2/0x410 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] bpf_trace_run1+0xf7/0x3b0 kernel/trace/bpf_trace.c:2360 __bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27 __traceiter_rcu_utilization+0x70/0xa0 include/trace/events/rcu.h:27 trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27 rcu_core+0x12d/0x1720 kernel/rcu/tree.c:2439 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 89 57 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90003607ca0 EFLAGS: 00000206 RAX: e675f0c1b7ea9900 RBX: 1ffff920006c0f9c RCX: e675f0c1b7ea9900 RDX: dffffc0000000000 RSI: ffffffff8aaab9a0 RDI: ffffffff8afc6640 RBP: ffffc90003607d90 R08: ffffffff90da3517 R09: 1ffffffff21b46a2 R10: dffffc0000000000 R11: fffffbfff21b46a3 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd354d8 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 do_unlinkat+0x33a/0x570 fs/namei.c:4394 __do_sys_unlink fs/namei.c:4439 [inline] __se_sys_unlink fs/namei.c:4437 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4437 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9ed2b15937 Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8 RSP: 002b:00007ffe08cc38f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 000055e8fd7f7320 RCX: 00007f9ed2b15937 RDX: 0000000000000000 RSI: 00007ffe08cc28b0 RDI: 00007ffe08cc3900 RBP: 00000000000001bb R08: 0000000000000064 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe08cc3900 R13: 000055e8fd7f5410 R14: 0000000000000008 R15: 000055e8fd7f7320 rcu: rcu_preempt kthread starved for 10094 jiffies! g23793 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:27088 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8145 Comm: dhcpcd-run-hook Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__lock_acquire+0x680d/0x7c80 kernel/locking/lockdep.c:5038 Code: 07 80 c1 03 38 c1 0f 8c c6 99 ff ff 48 89 df e8 59 66 75 00 49 b8 00 00 00 00 00 fc ff df e9 af 99 ff ff 48 c7 c1 60 a4 ea 96 <80> e1 07 80 c1 03 38 c1 0f 8c b9 99 ff ff 48 c7 c7 60 a4 ea 96 e8 RSP: 0018:ffffc900000075e0 EFLAGS: 00000002 RAX: 0000000000000004 RBX: ffff8880256fc6d8 RCX: ffffffff96eaa460 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cd2fba0 RBP: ffffc90000007828 R08: dffffc0000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1c950fe R12: 0000000000000000 R13: ffffffff9070ce90 R14: ffffffff8cd2fba8 R15: 0000000000000000 FS: 00007fda10410c80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005621a8b5c138 CR3: 000000002d9a5000 CR4: 00000000003506f0 Call Trace: lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] trace_call_bpf+0xe4/0x690 kernel/trace/bpf_trace.c:142 perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10262 perf_trace_lock_acquire+0x32a/0x3e0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x3e2/0x410 kernel/locking/lockdep.c:5725 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:522 [inline] try_to_wake_up+0x60/0x1140 kernel/sched/core.c:4232 wakeup_softirqd kernel/softirq.c:80 [inline] handle_softirqs+0x5fe/0x820 kernel/softirq.c:601 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 89 57 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc9000bf47ce0 EFLAGS: 00000206 RAX: c3934753e9f17a00 RBX: 1ffff920017e8fa4 RCX: c3934753e9f17a00 RDX: dffffc0000000000 RSI: ffffffff8aaab9a0 RDI: ffffffff8afc6640 RBP: ffffc9000bf47dd8 R08: ffffffff90da3517 R09: 1ffffffff21b46a2 R10: dffffc0000000000 R11: fffffbfff21b46a3 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd354d8 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 __fput+0x5e5/0x970 fs/file_table.c:392 __do_sys_close fs/open.c:1571 [inline] __se_sys_close+0x15f/0x220 fs/open.c:1556 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fda10560407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffc596b1c20 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007fda10410c80 RCX: 00007fda10560407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b RBP: 00005621a8b4f018 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000