rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6116/1:b..l P6142/1:b..l (detected by 1, t=10502 jiffies, g=20113, q=225) task:dhcpcd state:R running task stack:28384 pid: 6142 ppid: 3853 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] filemap_map_pages+0x1031/0x1390 mm/filemap.c:3353 do_fault_around mm/memory.c:4243 [inline] do_read_fault mm/memory.c:4258 [inline] do_fault mm/memory.c:4392 [inline] handle_pte_fault mm/memory.c:4650 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x2580/0x43c0 mm/memory.c:4883 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 RIP: 0033:0x7fdc240ed340 RSP: 002b:00007ffe17d2e5b8 EFLAGS: 00010246 RAX: 00005598b1ba9485 RBX: 00007ffe17d2eac0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00005598b1ba9485 RDI: 00007ffe17d2eac0 RBP: 00005598b1ba9485 R08: 00007ffe17d2ed80 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe17d2eb88 R14: 0000000000000000 R15: 00005598b1ba9485 task:syz.1.423 state:R running task stack:23488 pid: 6116 ppid: 4184 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] filemap_map_pages+0x1031/0x1390 mm/filemap.c:3353 do_fault_around mm/memory.c:4243 [inline] do_read_fault mm/memory.c:4258 [inline] do_fault mm/memory.c:4392 [inline] handle_pte_fault mm/memory.c:4650 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x2580/0x43c0 mm/memory.c:4883 faultin_page mm/gup.c:976 [inline] __get_user_pages+0x93e/0x11c0 mm/gup.c:1197 __get_user_pages_locked mm/gup.c:1382 [inline] get_dump_page+0x188/0x670 mm/gup.c:1838 dump_user_range+0x54/0x340 fs/coredump.c:1013 elf_core_dump+0x2ff7/0x3530 fs/binfmt_elf.c:2285 do_coredump+0x1419/0x2960 fs/coredump.c:894 get_signal+0x40a/0x12c0 kernel/signal.c:2886 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:320 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1504 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 RIP: 0033:0x7fab2c6a1ed1 RSP: 002b:0000000000000050 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007fab2c8f9090 RCX: 00007fab2c6a1ec9 RDX: 0000000000000000 RSI: 0000000000000050 RDI: 0000000000904000 RBP: 00007fab2c724f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fab2c8f9128 R14: 00007fab2c8f9090 R15: 00007ffc78f17658 rcu: rcu_preempt kthread starved for 9875 jiffies! g20113 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:28032 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:730 Code: bf 48 89 df e8 86 f5 09 f8 eb b5 e8 3f b0 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d f7 83 53 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2 RAX: 6c5b7db16bcd6400 RBX: ffff88813fe40000 RCX: 6c5b7db16bcd6400 RDX: 0000000000000001 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a480 RBP: ffffc90000d67e80 R08: dffffc0000000000 R09: ffffed1017227662 R10: ffffed1017227662 R11: 1ffff11017227661 R12: ffffffff8d6991e8 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11027fc8000 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112 cpuidle_idle_call kernel/sched/idle.c:194 [inline] do_idle+0x21b/0x5b0 kernel/sched/idle.c:306 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281 secondary_startup_64_no_verify+0xb1/0xbb