rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4264/1:b..l
	(detected by 0, t=10502 jiffies, g=7913, q=51 ncpus=2)
task:udevd           state:R  running task     stack:27584 pid:4264  ppid:3638   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock kernel/sched/wait.c:140 [inline]
 __wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:208
 sock_def_readable+0x15b/0x280 net/core/sock.c:3308
 unix_dgram_sendmsg+0x107b/0x16c0 net/unix/af_unix.c:2085
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 sock_write_iter+0x2b5/0x3a0 net/socket.c:1143
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 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: 0033:0x7fe464ea7407
RSP: 002b:00007ffea00f7900 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe465606880 RCX: 00007fe464ea7407
RDX: 0000000000000000 RSI: 00007ffea00f79a7 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fe4656066e8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10533 jiffies! g7913 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:27848 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:1965
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4276 Comm: syz-executor233 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:mark_lock+0x9c/0x320 kernel/locking/lockdep.c:4606
Code: 89 c7 41 81 e7 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 40 d2 ad 90 be 08 00 00 00 e8 3c 42 6d 00 4c 0f a3 3d 84 2f 4a 0f <73> 10 4b 8d 04 7f c1 e0 06 4c 8d b8 00 51 46 90 eb 24 48 c7 c0 20
RSP: 0018:ffffc900001e0700 EFLAGS: 00000057
RAX: 0000000000000001 RBX: ffff88802ffa1dc0 RCX: ffffffff8163a2b4
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90add250
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff215ba4b
R10: fffffbfff215ba4b R11: 1ffffffff215ba4a R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88802ffa28f0 R15: 00000000000000a2
FS:  00007fa51c1e16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa51c1e0e40 CR3: 000000007c287000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 mark_usage kernel/locking/lockdep.c:4520 [inline]
 __lock_acquire+0xc25/0x7c50 kernel/locking/lockdep.c:5003
 reacquire_held_locks+0x2f9/0x590 kernel/locking/lockdep.c:5187
 __lock_release kernel/locking/lockdep.c:5376 [inline]
 lock_release+0x340/0x910 kernel/locking/lockdep.c:5682
 rcu_lock_release include/linux/rcupdate.h:355 [inline]
 rcu_read_unlock include/linux/rcupdate.h:824 [inline]
 __lock_task_sighand+0x2b0/0x2d0 kernel/signal.c:1416
 lock_task_sighand include/linux/sched/signal.h:745 [inline]
 send_sigqueue+0x159/0x600 kernel/signal.c:1979
 posix_timer_event kernel/time/posix-timers.c:360 [inline]
 posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386
 __run_hrtimer kernel/time/hrtimer.c:1752 [inline]
 __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1816
 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1878
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 2e 31 43 f7 48 89 df e8 86 f6 43 f7 e8 91 e8 66 f7 fb bf 01 00 00 00 <e8> 36 74 37 f7 65 8b 05 07 35 e2 75 85 c0 74 02 5b c3 e8 54 46 e0
RSP: 0018:ffffc90003c47bb8 EFLAGS: 00000286
RAX: 252a6f8fa693c300 RBX: ffff88802f556f00 RCX: 252a6f8fa693c300
RDX: dffffc0000000000 RSI: ffffffff8a8c0460 RDI: 0000000000000001
RBP: ffff88802f557398 R08: dffffc0000000000 R09: ffffed1005eaade1
R10: ffffed1005eaade1 R11: 1ffff11005eaade0 R12: 1ffff11005eaae73
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1163/0x1350 kernel/signal.c:2874
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 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: 0033:0x7fa51c228347
Code: 14 25 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1c 00 00 90 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 b0 ff ff ff f7 d8 64 89
RSP: 002b:00007fa51c1e1218 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fa51c2ab308 RCX: 00007fa51c228349
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa51c2ab308
RBP: 00007fa51c2ab300 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000140
R13: 000020000006b000 R14: 0000200000000100 R15: 0000200000000680
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.410 msecs
sched: RT throttling activated