rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3561/1:b..l
	(detected by 0, t=10503 jiffies, g=45897, q=4)
task:udevd           state:R  running task     stack:22672 pid: 3561 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_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:404 [inline]
 fast_dput+0x11e/0x280 fs/dcache.c:-1
 dput+0xb7/0x1a0 fs/dcache.c:880
 path_put fs/namei.c:559 [inline]
 terminate_walk+0x38e/0x540 fs/namei.c:678
 path_lookupat+0x319/0x440 fs/namei.c:2480
 filename_lookup+0x214/0x540 fs/namei.c:2492
 user_path_at_empty+0x40/0x190 fs/namei.c:2891
 do_readlinkat+0xd9/0x490 fs/stat.c:442
 __do_sys_readlink fs/stat.c:475 [inline]
 __se_sys_readlink fs/stat.c:472 [inline]
 __x64_sys_readlink+0x7b/0x90 fs/stat.c:472
 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: 0033:0x7f34599c03a7
RSP: 002b:00007fffad2b8988 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fffad2b8e60 RCX: 00007f34599c03a7
RDX: 0000000000000400 RSI: 00007fffad2b8990 RDI: 00007fffad2b8e60
RBP: 00007fffad2b8990 R08: 000055a011732da4 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 0000000000000100 R14: 0000559fd217dbe0 R15: 00007fffad2b98e0
 </TASK>
rcu: rcu_preempt kthread starved for 10525 jiffies! g45897 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:28016 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: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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 13975 Comm: syz.1.2410 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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: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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 49 97 f7 48 89 df e8 f6 21 98 f7 e8 01 17 b9 f7 fb bf 01 00 00 00 <e8> d6 28 8c f7 65 8b 05 67 26 3c 76 85 c0 74 02 5b c3 e8 b4 33 3a
RSP: 0018:ffffc90003f6fb50 EFLAGS: 00000282
RAX: c931ac08efc6f200 RBX: ffff8880756eca00 RCX: c931ac08efc6f200
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: 0000000000000001
RBP: ffffc90003f6fcb0 R08: ffff8880756eca03 R09: 1ffff1100eadd940
R10: dffffc0000000000 R11: ffffed100eadd941 R12: dffffc0000000000
R13: 0000000100000000 R14: 0000000000000000 R15: 0000000000000020
 set_current_blocked kernel/signal.c:3072 [inline]
 signal_delivered kernel/signal.c:2936 [inline]
 signal_setup_done+0x2e6/0x490 kernel/signal.c:2947
 handle_signal arch/x86/kernel/signal.c:842 [inline]
 arch_do_signal_or_restart+0xedc/0x12c0 arch/x86/kernel/signal.c:869
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe68f4f0d90
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 3a 22 07 00 e8 65 65 f9 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007fe68d72ab38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fe68f74afa8 RCX: 00007fe68f4d1819
RDX: 00007fe68d72ab40 RSI: 00007fe68d72ac70 RDI: 0000000000000021
RBP: 00007fe68f74afa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe68f74b038 R14: 00007ffcd025af80 R15: 00007ffcd025b068
 </TASK>