rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5234/1:b..l rcu: (detected by 1, t=10502 jiffies, g=51465, q=329 ncpus=2) task:udevd state:R running task stack:23048 pid:5234 tgid:5234 ppid:1 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b 16 26 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900030577d8 EFLAGS: 00000206 RAX: c025f7b1a07a9800 RBX: 0000000000000000 RCX: c025f7b1a07a9800 RDX: 0000000000000001 RSI: ffffffff8dd9240a RDI: ffffffff8c03aa60 RBP: ffffffff8173bd25 R08: 0000000000000000 R09: ffffffff8173bd25 R10: ffffc90003057998 R11: ffffffff81ac5170 R12: 0000000000000002 R13: ffffffff8e33d260 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4945 [inline] slab_alloc_node mm/slub.c:5244 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5251 getname_flags+0xb8/0x540 fs/namei.c:146 getname include/linux/fs.h:2924 [inline] do_sys_openat2+0xbc/0x1c0 fs/open.c:1429 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcfd8ea7407 RSP: 002b:00007ffeb700c9a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fcfd9603880 RCX: 00007fcfd8ea7407 RDX: 0000000000080141 RSI: 0000563fd684f02e RDI: ffffffffffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g51465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=34550 rcu: rcu_preempt kthread starved for 10502 jiffies! g51465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27200 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline] RIP: 0010:lock_acquire+0x150/0x360 kernel/locking/lockdep.c:5871 Code: c7 0a 24 d9 8d e8 d0 82 e7 09 b8 ff ff ff ff 65 0f c1 05 d3 56 26 11 83 f8 01 0f 85 c9 00 00 00 48 c7 44 24 30 00 00 00 00 9c <8f> 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 RSP: 0018:ffffc90000007b38 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 59264617b8773b00 RDX: 0000000000000000 RSI: ffffffff8dd9240a RDI: ffffffff8c03aa60 RBP: ffffffff84d5225b R08: 0000000000000000 R09: ffffffff84d5225b R10: ffffc90000007ca0 R11: fffff52000000f96 R12: 0000000000000000 R13: ffffffff99ed5d88 R14: 0000000000000001 R15: 0000000000000046 FS: 0000000000000000(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000000c0 CR3: 0000000033e9a000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 4a 23 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6 RAX: 59264617b8773b00 RBX: ffffffff8196a2b7 RCX: 59264617b8773b00 RDX: 0000000000000001 RSI: ffffffff8dba2d53 RDI: ffffffff8c03aa60 RBP: ffffffff8e007ea8 R08: ffff8880b8632fdb R09: 1ffff110170c65fb R10: dffffc0000000000 R11: ffffed10170c65fc R12: ffffffff8fc39670 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a38 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147