rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3638/1:b..l
	(detected by 1, t=10502 jiffies, g=9445, q=45 ncpus=2)
task:udevd           state:R  running task     stack:25104 pid:3638  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:debug_lockdep_rcu_enabled+0x9/0x30 kernel/rcu/update.c:280
Code: 20 04 8c 8a 48 c7 c6 00 28 8c 8a e8 71 23 35 f7 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 31 c0 83 3d e7 93 07 04 00 <74> 1d 83 3d 72 c7 07 04 00 74 14 65 48 8b 0d 44 97 ea 75 31 c0 83
RSP: 0018:ffffc900032f7760 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc9000092fee8 RCX: 884db6fe2fb0b900
RDX: 0000000000000000 RSI: ffffffff8a8c1700 RDI: ffffffff8adef760
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: ffff88802721e2f0
R13: ffffffff81e52b5b R14: ffffc90000200000 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:792 [inline]
 __d_lookup+0xb1/0x7c0 fs/dcache.c:2490
 lookup_fast+0x7c/0x4d0 fs/namei.c:1656
 walk_component fs/namei.c:2002 [inline]
 link_path_walk+0x5f2/0xe50 fs/namei.c:2333
 path_openat+0x276/0x2e70 fs/namei.c:3787
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3818
 do_sys_openat2+0x142/0x490 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbc5e0a7407
RSP: 002b:00007ffd989fbf80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fbc5e789880 RCX: 00007fbc5e0a7407
RDX: 0000000000080000 RSI: 00007ffd989fc100 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055b1e9ebe7f5
R13: 000055b1e9ebe7f5 R14: 0000000000000001 R15: 00007ffd98a00750
 </TASK>
rcu: rcu_preempt kthread starved for 10535 jiffies! g9445 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:26880 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4523 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__lock_acquire+0xf00/0x7c50 kernel/locking/lockdep.c:-1
Code: 50 42 0f b6 04 00 84 c0 0f 85 d4 5b 00 00 41 33 1f f7 c3 00 60 00 00 74 11 49 c7 c5 ff ff ff ff c7 44 24 38 00 00 00 00 eb 06 <b0> 01 89 44 24 38 4c 89 b4 24 a8 00 00 00 48 8b 44 24 50 42 0f b6
RSP: 0018:ffffc900036676c0 EFLAGS: 00000046
RAX: ffff88802c0f6418 RBX: 0000000000000000 RCX: ffffffff96be9101
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90ae2270
RBP: ffffc90003667910 R08: dffffc0000000000 R09: fffffbfff215c44f
R10: fffffbfff215c44f R11: 1ffffffff215c44e R12: ffff88802c0f5940
R13: ffffffffffffffff R14: ffff88802c0f6420 R15: ffff88802c0f6440
FS:  0000555576e7b500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f063fff CR3: 0000000055f1e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __might_fault+0xc2/0x120 mm/memory.c:5852
 __clear_user arch/x86/include/asm/uaccess_64.h:96 [inline]
 copy_fpstate_to_sigframe+0x1a6/0xcb0 arch/x86/kernel/fpu/signal.c:216
 get_sigframe arch/x86/kernel/signal.c:297 [inline]
 __setup_rt_frame arch/x86/kernel/signal.c:472 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:784 [inline]
 handle_signal arch/x86/kernel/signal.c:828 [inline]
 arch_do_signal_or_restart+0x622/0x1240 arch/x86/kernel/signal.c:873
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f853238f749
Code: 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 01 48
RSP: 002b:00007fff8c35d778 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f85325e5fa0 RCX: 00007f853238f749
RDX: 0000200000000300 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f8532413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f85325e5fa0 R14: 00007f85325e5fa0 R15: 0000000000000004
 </TASK>
sched: RT throttling activated