rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3560/2:b..l
	(detected by 0, t=10502 jiffies, g=6685, q=38)
task:udevd           state:R  running task     stack:25728 pid: 3560 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_irq+0xb1/0x150 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:seqcount_lockdep_reader_access+0x17a/0x1c0 include/linux/seqlock.h:106
Code: ff 4d 85 ed 75 16 e8 c5 6f a3 ff eb 15 e8 be 6f a3 ff e8 f9 92 d4 07 4d 85 ed 74 ea e8 af 6f a3 ff fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 66 43 c7 44 27 09 00 00 43 c6 44 27 0b 00
RSP: 0018:ffffc90002e1f400 EFLAGS: 00000293
RAX: ffffffff81d45b71 RBX: 0000000000000000 RCX: ffff88807d179dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002e1f4c0 R08: dffffc0000000000 R09: fffffbfff1ad323e
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: dffffc0000000000
R13: 0000000000000200 R14: ffffffff81d4370c R15: 1ffff920005c3e80
 read_seqbegin include/linux/seqlock.h:897 [inline]
 read_seqbegin_or_lock include/linux/seqlock.h:1191 [inline]
 prepend_path+0x2bc/0xbb0 fs/d_path.c:172
 d_absolute_path+0x9e/0x140 fs/d_path.c:235
 tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline]
 tomoyo_realpath_from_path+0x331/0x610 security/tomoyo/realpath.c:276
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x183/0x360 security/tomoyo/file.c:771
 security_file_open+0x5e/0xa0 security/security.c:1668
 do_dentry_open+0x322/0xf80 fs/open.c:813
 do_open fs/namei.c:3608 [inline]
 path_openat+0x2682/0x2f30 fs/namei.c:3742
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
 do_sys_openat2+0x142/0x4a0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1280
 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: 0033:0x7f698afd8c3a
RSP: 002b:00007ffd3c6a1fc8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000560536688c20 RCX: 00007f698afd8c3a
RDX: 0000000000090800 RSI: 0000560536506dc0 RDI: 00000000ffffff9c
RBP: 0000560536506dc0 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 00005605365037b0
R13: 00000000000000fd R14: 0000560525cb5be0 R15: 00007ffd3c6a22d0
 </TASK>
rcu: rcu_preempt kthread starved for 10531 jiffies! g6685 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:27168 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 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: 4382 Comm: syz.1.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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+0x10c8/0x1220 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+0x831/0x1110 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:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 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:lock_release+0x584/0x870 kernel/locking/lockdep.c:5647
Code: 00 00 00 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 75 75 f7 44 24 50 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 66 43 c7 44 2f 09 00 00 43 c6 44 2f 0b 00
RSP: 0018:ffffc9000397fa20 EFLAGS: 00000206
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: 54445bd727c7e100
RDX: 0000000000000000 RSI: ffffffff8a0b2ac0 RDI: ffffffff8a59a480
RBP: ffffc9000397fb30 R08: dffffc0000000000 R09: fffffbfff1ad323e
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: ffff88802b148af0
R13: dffffc0000000000 R14: ffff88802b148ae0 R15: 1ffff9200072ff50
 __copy_from_user include/linux/uaccess.h:109 [inline]
 check_xstate_in_sigframe arch/x86/kernel/fpu/signal.c:33 [inline]
 __fpu_restore_sig arch/x86/kernel/fpu/signal.c:317 [inline]
 fpu__restore_sig+0x203/0xf50 arch/x86/kernel/fpu/signal.c:466
 restore_sigcontext arch/x86/kernel/signal.c:139 [inline]
 __ia32_sys_rt_sigreturn+0x649/0x790 arch/x86/kernel/signal.c:674
 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: 0033:0x7ff7415a7ec7
Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89
RSP: 002b:00007ff73f80f0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007ff7417fefa8 RCX: 00007ff7415a7ec9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff7417fefa8
RBP: 00007ff7417fefa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff7417ff038 R14: 00007ffc1e6e3a00 R15: 00007ffc1e6e3ae8
 </TASK>