rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3562/1:b..l
	(detected by 0, t=10502 jiffies, g=28165, q=135)
task:udevd           state:R  running task     stack:23216 pid: 3562 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:rcu_read_lock_held_common kernel/rcu/update.c:104 [inline]
RIP: 0010:rcu_read_lock_held+0x1/0x40 kernel/rcu/update.c:309
Code: 8f e8 43 05 5a 00 eb cf 90 0f b6 05 b5 ba 25 0c c3 0f 1f 84 00 00 00 00 00 e8 eb df 00 00 e9 c6 e1 00 00 66 0f 1f 44 00 00 53 <e8> 7a cf 57 08 85 c0 74 26 31 db e8 7f b2 00 00 84 c0 74 20 e8 d6
RSP: 0018:ffffc90002ebf6f0 EFLAGS: 00000246
RAX: ffffffff81cee5c7 RBX: 0000000000000000 RCX: ffff88807cb00000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888075d6f608 R08: ffffc9000052745f R09: 1ffff920000a4e8b
R10: dffffc0000000000 R11: fffff520000a4e8c R12: dffffc0000000000
R13: ffffc90000527458 R14: 1ffff920000a4e8b R15: ffff888075d74c00
 hlist_bl_first_rcu include/linux/rculist_bl.h:24 [inline]
 __d_lookup+0x162/0x760 fs/dcache.c:2432
 lookup_fast+0xd7/0x720 fs/namei.c:1629
 walk_component+0x81/0x460 fs/namei.c:1980
 link_path_walk+0x665/0xd70 fs/namei.c:-1
 path_lookupat+0x9d/0x440 fs/namei.c:2462
 filename_lookup+0x214/0x540 fs/namei.c:2492
 user_path_at_empty+0x40/0x190 fs/namei.c:2891
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x107/0x500 fs/stat.c:221
 vfs_fstatat fs/stat.c:243 [inline]
 __do_sys_newfstatat fs/stat.c:411 [inline]
 __se_sys_newfstatat fs/stat.c:405 [inline]
 __x64_sys_newfstatat+0x15f/0x200 fs/stat.c:405
 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: 0033:0x7fded1807b0a
RSP: 002b:00007ffcc14f73c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007ffcc14f7860 RCX: 00007fded1807b0a
RDX: 00007ffcc14f73d0 RSI: 00007ffcc14f7860 RDI: 00000000ffffff9c
RBP: 0000559d4944d910 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcc14f7460
R13: 00000000000000ff R14: 0000559d197a4be0 R15: 00007ffcc14f7f20
 </TASK>
rcu: rcu_preempt kthread starved for 10533 jiffies! g28165 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:27800 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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:1914
 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <IRQ>
 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:1818
 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+0x4ad/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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: b7 48 89 df e8 f6 ea f8 f7 eb ad e8 8f af f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d b7 96 60 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c007dc8 EFLAGS: 000002c6
RAX: af728cff0f7b9800 RBX: ffffffff8c0bc480 RCX: af728cff0f7b9800
RDX: 0000000000000001 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: ffffffff8c007ef8 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffffffff1817890
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffffffff1800fc4
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x21f/0x580 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_kernel+0x489/0x540 init/main.c:1154
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>