rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3093/1:b..l (detected by 1, t=10502 jiffies, g=127305, q=136 ncpus=2) task:udevd state:R running task stack:22600 pid:3093 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6727 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6751 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] __d_lookup+0x61b/0x790 fs/dcache.c:2506 lookup_fast+0x74/0x490 fs/namei.c:1648 open_last_lookups fs/namei.c:3521 [inline] path_openat+0x640/0x2e60 fs/namei.c:3782 do_filp_open+0x230/0x480 fs/namei.c:3812 do_sys_openat2+0x13b/0x4f0 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+0x243/0x290 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f573e9169a4 RSP: 002b:00007ffea0faae80 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f573e9169a4 RDX: 0000000000080000 RSI: 00007ffea0faafb8 RDI: 00000000ffffff9c RBP: 00007ffea0faafb8 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000 R13: 000055b592a0db42 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10488 jiffies! g127305 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:25208 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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: 17386 Comm: syz.3.2525 Not tainted 6.1.105-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:__lock_acquire+0xc8d/0x1f80 kernel/locking/lockdep.c:5019 Code: 00 00 e8 26 5a 00 00 31 f6 85 c0 0f 84 8f 08 00 00 48 c7 c0 60 21 f3 91 48 c1 e8 03 48 bf 00 00 00 00 00 fc ff df 0f b6 04 38 <84> c0 0f 85 ea 0b 00 00 83 3d a4 9b 88 10 00 75 39 48 63 9c 24 80 RSP: 0018:ffffc90000007a20 EFLAGS: 00000802 RAX: 0000000000000004 RBX: ffff888074616404 RCX: ffffffff816ae04a RDX: 0000000000000000 RSI: 0000000000000000 RDI: dffffc0000000000 RBP: ffff888074616420 R08: dffffc0000000000 R09: fffffbfff20e7469 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888074616418 R13: ffff888074615940 R14: ffff888074616440 R15: 1ffff1100e8c2c88 FS: 00007fa35d1656c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33f09ff8 CR3: 0000000060db5000 CR4: 00000000003506f0 Call Trace: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 posix_timer_fn+0x2f/0x390 kernel/time/posix-timers.c:374 __run_hrtimer kernel/time/hrtimer.c:1686 [inline] __hrtimer_run_queues+0x5e5/0xe50 kernel/time/hrtimer.c:1750 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 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: d1 9d f5 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0e eb ba f6 48 89 df e8 76 28 bc f6 e8 41 b5 e1 f6 fb bf 01 00 00 00 f6 b8 ae f6 65 8b 05 97 c1 52 75 85 c0 74 02 5b c3 e8 44 e5 50 RSP: 0018:ffffc90003c3fb30 EFLAGS: 00000286 RAX: 9bc3fdb2659f1300 RBX: ffff888027f42e40 RCX: ffffffff91f32103 RDX: dffffc0000000000 RSI: ffffffff8b0c0260 RDI: 0000000000000001 RBP: ffffc90003c3fc70 R08: dffffc0000000000 R09: ffffed1004fe85c9 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff11004fe865b R13: 000000001c000004 R14: 0000000000000021 R15: ffff888027f432d8 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x154b/0x17d0 kernel/signal.c:2873 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 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+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa35c3799b9 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:00007fa35d1650e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007fa35c516138 RCX: 00007fa35c3799b9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa35c516138 RBP: 00007fa35c516130 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa35c51613c R13: 0000000000000000 R14: 00007ffcddb5b430 R15: 00007ffcddb5b518