rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11780/1:b..l rcu: (detected by 0, t=10502 jiffies, g=67137, q=2205 ncpus=2) task:udevd state:R running task stack:25688 pid:11780 tgid:11780 ppid:5195 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 60 6d f4 8d e8 6f b8 1d 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 65 ff 05 60 72 d2 10 e8 db 9f a7 09 89 RSP: 0018:ffffc9000e61f7f0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff9024af01 RCX: ffff88807d67bd00 RDX: ffffc9000e61f901 RSI: dffffc0000000000 RDI: ffffc9000e61f8d0 RBP: dffffc0000000000 R08: ffffc9000e61fdf0 R09: ffffc9000e61f918 R10: dffffc0000000000 R11: fffff52001cc3f25 R12: ffffc9000e61fe00 R13: ffffc9000e618000 R14: ffffc9000e61f8c8 R15: ffffffff8173ff45 rcu_read_unlock include/linux/rcupdate.h:895 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x1965/0x2390 arch/x86/kernel/unwind_orc.c:680 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:339 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4948 [inline] slab_alloc_node mm/slub.c:5258 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5265 getname_flags+0xb8/0x540 fs/namei.c:146 user_path_at+0x24/0x60 fs/namei.c:3566 do_utimes_path fs/utimes.c:96 [inline] do_utimes+0x131/0x2a0 fs/utimes.c:141 __do_sys_utimensat fs/utimes.c:160 [inline] __se_sys_utimensat fs/utimes.c:144 [inline] __x64_sys_utimensat+0x14f/0x230 fs/utimes.c:144 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8131b15a1a RSP: 002b:00007ffc89be7758 EFLAGS: 00000246 ORIG_RAX: 0000000000000118 RAX: ffffffffffffffda RBX: 0000000000006180 RCX: 00007f8131b15a1a RDX: 0000000000000000 RSI: 000055d969372430 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 000055d96937f1d0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055d969372430 R15: 000055d969389e00 rcu: rcu_preempt kthread starved for 10294 jiffies! g67137 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:26288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: ce 73 c1 f5 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 83 80 19 00 f3 0f 1e fa fb f4 a3 73 c1 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 7058c95b621ad400 RBX: ffffffff81974b6a RCX: 7058c95b621ad400 RDX: 0000000000000001 RSI: ffffffff8d7831da RDI: ffffffff8bc00c60 RBP: ffffc90000197f10 R08: ffff8880b89336db R09: 1ffff110171266db R10: dffffc0000000000 R11: ffffed10171266dc R12: ffffffff8f815070 R13: 1ffff1100395cb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888126184000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556e07e588 CR3: 000000001f340000 CR4: 0000000000350ef0 Call Trace: 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:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147