rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5874/1:b..l rcu: (detected by 1, t=10502 jiffies, g=32757, q=407 ncpus=2) task:udevd state:R running task stack:23528 pid:5874 tgid:5874 ppid:5197 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191 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:rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:753 Code: c3 d8 46 7e 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 59 73 d5 10 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f c3 cc cc cc cc cc e8 51 db 8b ff eb e8 48 c7 c7 80 77 RSP: 0018:ffffc9000413f858 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 00007fb95bd11b0a RCX: aabf2c249a3b2800 RDX: ffff888058733d00 RSI: ffffffff8bc018c0 RDI: ffffffff8bc01880 RBP: 0000000000000001 R08: ffffffff81d0ecc6 R09: ffffffff8df419e0 R10: ffffc9000413f958 R11: ffffffff81ada230 R12: ffff888058733d00 R13: 0000000000000000 R14: ffffffff8d9a2dd8 R15: dffffc0000000000 rcu_read_lock include/linux/rcupdate.h:868 [inline] is_bpf_text_address+0x64/0x2b0 kernel/bpf/core.c:744 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 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:6663 [inline] kmem_cache_free+0x197/0x620 mm/slub.c:6774 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/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb95bd11b0a RSP: 002b:00007ffe51c9d678 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000000000000000e RCX: 00007fb95bd11b0a RDX: 00007ffe51c9d680 RSI: 00007ffe51c9d750 RDI: 00000000ffffff9c RBP: 00007ffe51c9e790 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe51c9ebb0 R13: 0000000000000000 R14: 0000000000000008 R15: 00005557437ae820 rcu: rcu_preempt kthread starved for 10543 jiffies! g32757 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:27256 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6864 __schedule_loop kernel/sched/core.c:6946 [inline] schedule+0x165/0x360 kernel/sched/core.c:6961 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: 93 ef 02 00 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 73 f0 0e 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 73b39777fded8300 RBX: ffffffff8197913a RCX: 73b39777fded8300 RDX: 0000000000000001 RSI: ffffffff8d783537 RDI: ffffffff8bc018e0 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f813370 R13: 1ffff110039deb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3ff82c CR3: 0000000030cf8000 CR4: 00000000003526f0 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