rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=15901, q=654 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294968259-4294957756), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10504 jiffies! g15901 f0x2 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:28984 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 50 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: krxrpcd rxrpc_peer_keepalive_worker RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20 arch/x86/include/asm/idtentry.h:674 Code: 16 b1 9c 0a e9 81 06 00 00 90 f3 0f 1e fa 0f 01 ca fc 6a ff e8 31 05 00 00 48 89 c4 48 89 e7 e8 26 b0 9c 0a e9 61 06 00 00 90 0f 1e fa 0f 01 ca fc 6a ff e8 11 05 00 00 48 89 c4 48 89 e7 e8 RSP: 0018:ffffc90000bb78b8 EFLAGS: 00000006 RAX: 000000000037eeeb RBX: ffff88801d35a540 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e15d8c3 RDI: ffff88801d35bc38 RBP: ffffc90000bb7940 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880274d4a80 R13: 0000000000000000 R14: ffffffff90fbe664 R15: ffff8880b853b4c0 FS: 0000000000000000(0000) GS:ffff8881241e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 0000000071842000 CR4: 00000000003526f0 Call Trace: RIP: 0010:finish_task_switch.isra.0+0x2cd/0x10c0 kernel/sched/core.c:5361 Code: ab 0a 00 00 41 c7 87 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 8d 7f 48 e8 b0 a4 ca 09 e8 4b ad 3c 00 fb 48 8d bb f8 16 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 RSP: 0018:ffffc90000bb78e8 EFLAGS: 00000206 context_switch kernel/sched/core.c:5513 [inline] __schedule+0x1264/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:202 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:232 [inline] RIP: 0010:tif_test_bit include/linux/thread_info.h:199 [inline] RIP: 0010:tif_need_resched include/linux/thread_info.h:215 [inline] RIP: 0010:need_resched include/linux/sched.h:2258 [inline] RIP: 0010:preempt_schedule_common+0x49/0xc0 kernel/sched/core.c:7421 Code: c3 65 ff 05 79 ee 95 08 65 8b 05 72 ee 95 08 25 ff ff ff 7f 83 f8 01 74 27 bf 01 00 00 00 e8 de 93 ff ff 65 ff 0d 57 ee 95 08 <80> 3b 00 75 55 48 8b 45 00 a8 10 75 ca 5b 5d 41 5c c3 cc cc cc cc RSP: 0018:ffffc90000bb7bc0 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffffed1003a6b4a8 RCX: 1ffff92000176f65 RDX: 0000000000000000 RSI: ffffffff8c3e9b00 RDI: ffffffff8e417928 RBP: ffff88801d35a540 R08: 0000000000000000 R09: fffffbfff21f7652 R10: ffffffff90fbb297 R11: 0000000000000000 R12: ffffffff81759c96 R13: 0000000000000000 R14: ffffffff90fbe664 R15: 0000000000000001 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] _raw_spin_unlock_irq+0x44/0x50 kernel/locking/spinlock.c:206 process_one_work+0x871/0x1940 kernel/workqueue.c:3291 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245