rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5236/1:b..l rcu: (detected by 1, t=10504 jiffies, g=18473, q=343 ncpus=2) task:udevd state:R running task stack:22800 pid:5236 tgid:5236 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 cb 68 03 11 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000f2df730 EFLAGS: 00000206 RAX: 643f94fe342fdc00 RBX: 0000000000000202 RCX: 643f94fe342fdc00 RDX: 0000000000000000 RSI: ffffffff8dbaa5db RDI: ffffffff8be34480 RBP: ffff8880717cc6f0 R08: ffff888079db13d3 R09: 1ffff1100f3b627a R10: dffffc0000000000 R11: ffffed100f3b627b R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8e13a160 R15: ffff8880717cbc00 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] __d_lookup+0x6da/0x780 fs/dcache.c:2413 lookup_fast+0x84/0x5b0 fs/namei.c:1766 walk_component fs/namei.c:2125 [inline] link_path_walk+0x642/0xea0 fs/namei.c:2497 path_openat+0x28c/0x3830 fs/namei.c:4042 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f791c715c3a RSP: 002b:00007ffd89babb78 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000561b86dc49f0 RCX: 00007f791c715c3a RDX: 0000000000090800 RSI: 0000561b86cad410 RDI: 00000000ffffff9c RBP: 0000561b86cad410 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 0000561b86cbe7b0 R13: 00000000000000ff R14: 0000561b71f18be0 R15: 00007ffd89babe00 rcu: rcu_preempt kthread starved for 10502 jiffies! g18473 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:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 7715 Comm: syz.1.430 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_single+0x3a9/0x590 kernel/smp.c:687 Code: 33 44 89 f6 83 e6 01 31 ff e8 83 7a 0b 00 41 83 e6 01 75 11 e8 38 76 0b 00 4d 89 fe eb 3f e8 2e 76 0b 00 eb 3c 4d 89 fe f3 90 <43> 0f b6 04 2c 84 c0 75 0f f7 03 01 00 00 00 74 1d e8 11 76 0b 00 RSP: 0018:ffffc900055bfaa0 EFLAGS: 00000246 RAX: ffffffff81b44f8f RBX: ffffc900055bfae8 RCX: 0000000000080000 RDX: ffffc90005103000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc900055bfb90 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6 R10: dffffc0000000000 R11: ffffffff81706100 R12: 1ffff92000ab7f5d R13: dffffc0000000000 R14: 1ffff92000ab7f58 R15: 1ffff92000ab7f58 FS: 00007fda2b9ab6c0(0000) GS:ffff888125d11000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3b1c57 CR3: 000000007695a000 CR4: 00000000003526f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: cpu_function_call kernel/events/core.c:154 [inline] perf_install_in_context+0x519/0x8f0 kernel/events/core.c:3065 __do_sys_perf_event_open kernel/events/core.c:13722 [inline] __se_sys_perf_event_open+0x193a/0x1d70 kernel/events/core.c:13364 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fda2ab8eec9 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:00007fda2b9ab038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fda2ade5fa0 RCX: 00007fda2ab8eec9 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00002000000001c0 RBP: 00007fda2ac11f91 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fda2ade6038 R14: 00007fda2ade5fa0 R15: 00007fff3ec72a38