rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5195/1:b..l rcu: (detected by 1, t=10502 jiffies, g=11069, q=459 ncpus=2) task:udevd state:R running task stack:25512 pid:5195 tgid:5195 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x6e/0x340 kernel/locking/lockdep.c:5833 Code: 10 83 f8 08 0f 83 af 01 00 00 89 c0 48 0f a3 05 58 a9 e3 0d 73 0d e8 21 25 09 00 84 c0 0f 84 d7 01 00 00 83 3d 72 d9 e3 0d 00 <0f> 84 f0 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 0c 68 89 00 RSP: 0018:ffffc900037d7818 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0baabd3f81862600 RDX: 0000000000000000 RSI: ffffffff8bc08340 RDI: ffffffff8bc08300 RBP: ffffffff81743f85 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff81ada000 R12: 0000000000000002 R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6668 [inline] kmem_cache_free+0x197/0x620 mm/slub.c:6779 file_free fs/file_table.c:71 [inline] __fput+0x6c2/0xa70 fs/file_table.c:481 fput_close_sync+0x113/0x220 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1558 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0717646a67 RSP: 002b:00007ffeb26c20b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 000055bbc388b5f0 RCX: 00007f0717646a67 RDX: 000000000000d091 RSI: 00007f0717722b20 RDI: 000000000000000e RBP: 000055bbc37f4b10 R08: 0000000000005050 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000206 R12: 000055bbc37f57b0 R13: 00000000000000fe R14: 000055bbbf370be0 R15: 00007ffeb26c2370 rcu: rcu_preempt kthread starved for 10543 jiffies! g11069 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:27272 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 5e 93 b4 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 a0 0c 00 f3 0f 1e fa fb f4 33 93 b4 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: c6a6261a40738900 RBX: ffffffff81978eba RCX: c6a6261a40738900 RDX: 0000000000000001 RSI: ffffffff8d7921b8 RDI: ffffffff8bc08360 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f821e70 R13: 1ffff110038d6b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f46ac088f98 CR3: 00000000762ec000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147