rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6212/1:b..l rcu: (detected by 0, t=10502 jiffies, g=34761, q=328 ncpus=2) task:udevd state:R running task stack:22728 pid:6212 tgid:6212 ppid:5195 task_flags:0x40014c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5030 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:__sanitizer_cov_trace_const_cmp4+0x83/0x90 kernel/kcov.c:316 Code: 8d 52 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c8 0d 9d 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9000c027450 EFLAGS: 00000293 RAX: ffffffff82340592 RBX: ffff88801bb80000 RCX: 0000000000000000 RDX: ffff88803435bd00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8232572e R10: 000000000000000e R11: ffffffff81adcc30 R12: 000000000006b06d R13: dffffc0000000000 R14: ffff88813fffa5b0 R15: 0000000000001000 lookup_page_ext mm/page_ext.c:254 [inline] page_ext_lookup+0xf2/0x180 mm/page_ext.c:509 page_ext_iter_begin include/linux/page_ext.h:132 [inline] __update_page_owner_free_handle+0x103/0x470 mm/page_owner.c:284 __reset_page_owner+0x85/0x1f0 mm/page_owner.c:321 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xd22/0x1470 mm/page_alloc.c:3000 folios_put_refs+0x584/0x670 mm/swap.c:1002 free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline] tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 exit_mmap+0x439/0xb40 mm/mmap.c:1290 __mmput+0x118/0x430 kernel/fork.c:1173 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x658/0x2310 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 __do_sys_exit_group kernel/exit.c:1123 [inline] __se_sys_exit_group kernel/exit.c:1121 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7f75f1cf16c5 RSP: 002b:00007fff84218258 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000560252c5ec60 RCX: 00007f75f1cf16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 0000560252c57910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff842182a0 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10543 jiffies! g34761 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:27208 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5257 [inline] __schedule+0x14bc/0x5030 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: 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 40 0c 00 f3 0f 1e fa fb f4 c8 f2 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 1d4492d8b64a4700 RBX: ffffffff8197a977 RCX: 1d4492d8b64a4700 RDX: 0000000000000001 RSI: ffffffff8d790e8f RDI: ffffffff8bbf7760 RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f7df370 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a60 FS: 0000000000000000(0000) GS:ffff888125eb8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560252c60a38 CR3: 00000000519da000 CR4: 00000000003526f0 DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000404 DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400 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+0x3a7/0x410 init/main.c:1206 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