rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5897/1:b..l rcu: (detected by 0, t=10502 jiffies, g=11441, q=1052 ncpus=2) task:udevd state:R running task stack:23224 pid:5897 tgid:5897 ppid:5192 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:895 [inline] RIP: 0010:class_rcu_destructor include/linux/rcupdate.h:1195 [inline] RIP: 0010:unwind_next_frame+0x1967/0x2390 arch/x86/kernel/unwind_orc.c:680 Code: 8b 64 24 20 41 0f b6 04 2c 84 c0 0f 85 2d 03 00 00 41 c7 06 00 00 00 00 31 db e8 f4 32 d8 09 85 c0 74 3a e8 eb a7 32 00 84 c0 <75> 31 e8 e2 32 d8 09 85 c0 74 28 80 3d 98 15 14 0e 00 75 1f c6 05 RSP: 0018:ffffc9000400f838 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff9038fa01 RCX: 1c09ba2a27fa4700 RDX: ffffc9000400f901 RSI: ffffffff8bc076c0 RDI: ffffffff8bc07680 RBP: dffffc0000000000 R08: ffffc9000400fd00 R09: ffffc9000400f958 R10: dffffc0000000000 R11: fffff52000801f2d R12: ffffc9000400fd10 R13: ffffc90004008000 R14: ffffc9000400f908 R15: ffffffff8173cd25 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:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] 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:2523 [inline] slab_free mm/slub.c:6611 [inline] kmem_cache_free+0x19b/0x690 mm/slub.c:6721 vfs_fstatat+0x122/0x170 fs/stat.c:376 __do_sys_newfstatat fs/stat.c:542 [inline] __se_sys_newfstatat fs/stat.c:536 [inline] __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2c70311b0a RSP: 002b:00007ffe71a7d648 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000000000000000f RCX: 00007f2c70311b0a RDX: 00007ffe71a7d650 RSI: 00007ffe71a7d720 RDI: 00000000ffffff9c RBP: 00007ffe71a7e760 R08: 0000000000000064 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe71a7e770 R13: 0000000000000000 R14: 0000000000000008 R15: 000056141dbcef60 rcu: rcu_preempt kthread starved for 10417 jiffies! g11441 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 5e 33 c4 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 33 21 1c 00 f3 0f 1e fa fb f4 33 33 c4 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c6 RAX: 4710902771a3cd00 RBX: ffffffff8196bc07 RCX: 4710902771a3cd00 RDX: 0000000000000001 RSI: ffffffff8d7e8390 RDI: ffffffff8bc076e0 RBP: ffffffff8de07ea8 R08: ffff8880b8632fdb R09: 1ffff110170c65fb R10: dffffc0000000000 R11: ffffed10170c65fc R12: ffffffff8f9e1170 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a40 FS: 0000000000000000(0000) GS:ffff888125d0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffe8 CR3: 000000005a9fa000 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:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147