rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=faa4/0/0x1 softirq=15614/15615 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=11493, q=107 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__lock_acquire+0xaf4/0xd80 kernel/locking/lockdep.c:5243 Code: 54 24 10 48 89 e9 e8 1b 44 00 00 45 31 ed 85 c0 74 3b 41 f6 46 02 10 75 2e 48 8b 1c 24 48 89 ab e0 0a 00 00 8b 83 e8 0a 00 00 c0 89 83 e8 0a 00 00 83 f8 30 0f 83 b4 01 00 00 3b 05 ed 86 d1 RSP: 0018:ffffc90000a08b50 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88801d6cda00 RCX: 0e05dc09084f7800 RDX: 0000000000000001 RSI: ffff88801d6ce4f0 RDI: ffff88801d6cda00 RBP: 0ac0d5affe09d4ff R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000004008 R13: 0000000000000000 R14: ffff88801d6ce510 R15: 0000000000004008 FS: 0000000000000000(0000) GS:ffff88812509a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003c80 CR3: 0000000035800000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] advance_sched+0xa1e/0xca0 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x5a8/0xd40 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: de ae e0 f4 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 73 7f 18 00 f3 0f 1e fa fb f4 b3 ae e0 f4 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197dc0 EFLAGS: 00000282 RAX: 0e05dc09084f7800 RBX: ffffffff8197272e RCX: ffffffff8c2fb93c RDX: 0000000000000001 RSI: ffffffff8e6498ee RDI: ffffffff8ca1b720 RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2 R13: 1ffff11003ad9b40 R14: 0000000000000001 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x22e/0x5d0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.176 msecs rcu: rcu_preempt kthread starved for 10500 jiffies! g11493 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:26376 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b9/0x940 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1baa/0x2d40 kernel/smp.c:885 Code: b6 04 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 68 dc 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 18 d8 0b 00 eb 41 90 48 b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 RSP: 0018:ffffc90000117640 EFLAGS: 00000293 RAX: ffffffff81b6e2cd RBX: 1ffff110170e7e91 RCX: ffff88801c2fda00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000117840 R08: ffffffff81b6e298 R09: 1ffffffff20bfcce R10: dffffc0000000000 R11: fffffbfff20bfccf R12: ffff8880b863ad08 R13: ffff8880b873f488 R14: ffff8880b863ad00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124f9a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 000000000eb38000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2455 [inline] text_poke_bp_batch+0x354/0xb30 arch/x86/kernel/alternative.c:2665 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xc0/0x250 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac5/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 kthread+0x7b9/0x940 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245