rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18774/1:b..l P18821/1:b..l rcu: (detected by 1, t=10502 jiffies, g=101297, q=338 ncpus=2) task:dhcpcd-run-hook state:R running task stack:26744 pid:18821 tgid:18821 ppid:18812 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 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:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline] RIP: 0010:unwind_next_frame+0xe4a/0x23d0 arch/x86/kernel/unwind_orc.c:600 Code: 49 39 dc 0f 97 c0 20 c8 3c 01 0f 85 eb 0b 00 00 48 8d 43 08 4c 39 f8 0f 97 c1 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 d1 0b 00 00 <48> 89 df e8 ae 21 00 00 48 89 c3 48 bd 00 00 00 00 00 fc ff df 48 RSP: 0018:ffffc90003447318 EFLAGS: 00000202 RAX: ffffc90003447a01 RBX: ffffc90003447a18 RCX: 1ffff92000688e01 RDX: ffffffff90214286 RSI: 0000000000000002 RDI: ffffffff8bc08400 RBP: 1ffff92000688e7e R08: 0000000000000001 R09: ffffffff8df41b20 R10: ffffc90003447438 R11: ffffffff81ada390 R12: ffffc90003448000 R13: 1ffff92000688e7f R14: ffffc900034473e8 R15: ffffc90003440000 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:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x870/0x1b80 mm/mmap.c:1773 dup_mm kernel/fork.c:1529 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1581 copy_process+0x165d/0x3950 kernel/fork.c:2221 kernel_clone+0x21e/0x820 kernel/fork.c:2651 __do_sys_clone kernel/fork.c:2792 [inline] __se_sys_clone kernel/fork.c:2776 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776 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: 0033:0x7feb6067c636 RSP: 002b:00007ffc544dd000 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffc544dd008 RCX: 00007feb6067c636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 000055ca7be02e60 R08: 0000000000000000 R09: 0000000000000000 R10: 00007feb604e2f50 R11: 0000000000000246 R12: 000055ca7be05060 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 task:syz.6.2777 state:R running task stack:21112 pid:18774 tgid:18774 ppid:14084 task_flags:0x400640 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:-1 Code: 8b 5c 24 78 4c 8b 64 24 48 74 08 48 89 df e8 a9 c0 b3 00 48 8b 44 24 18 48 89 03 ba 10 00 00 00 4c 89 e7 31 f6 e8 72 c2 b3 00 <48> 8b 14 24 e9 ca 04 00 00 4c 89 64 24 18 4d 8d 6e 08 4c 89 e8 48 RSP: 0018:ffffc900047a5ed8 EFLAGS: 00000246 RAX: ffffc900047a5ff8 RBX: ffffc900047a5fe0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900047a6008 RBP: dffffc0000000000 R08: ffffc900047a6007 R09: 0000000000000000 R10: ffffc900047a5ff8 R11: fffff520008f4c01 R12: ffffc900047a5ff8 R13: 1ffff920008f4bf7 R14: ffffc900047a5fa8 R15: ffffc900047a5ff0 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1890 [inline] shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1932 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2556 shmem_get_folio mm/shmem.c:2662 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3315 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3490 __kernel_write_iter+0x428/0x910 fs/read_write.c:619 dump_emit_page fs/coredump.c:1298 [inline] dump_user_range+0x8a0/0xc90 fs/coredump.c:1372 elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111 coredump_write+0x1121/0x18b0 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x177/0x660 kernel/entry/common.c:196 exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7ffb0f98f751 RSP: 002b:000000000000a420 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007ffb0fbe5fa0 RCX: 00007ffb0f98f749 RDX: 0000000000000000 RSI: 000000000000a420 RDI: 0000000000022080 RBP: 00007ffb0fa13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffb0fbe6038 R14: 00007ffb0fbe5fa0 R15: 00007ffc74c7aaa8 rcu: rcu_preempt kthread starved for 10604 jiffies! g101297 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:27064 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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 b3 70 0c 00 f3 0f 1e fa fb f4 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 868d821b3fcd0c00 RBX: ffffffff8197928a RCX: 868d821b3fcd0c00 RDX: 0000000000000001 RSI: ffffffff8d793d57 RDI: ffffffff8bc08460 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822c70 R13: 1ffff110039dcb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f32000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff5bb3adf98 CR3: 000000002feda000 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