rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 ticks this GP) idle=3a04/1/0x4000000000000000 softirq=18631/18631 fqs=6 rcu: (detected by 0, t=10502 jiffies, g=9569, q=479 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6138 Comm: syz.3.20 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x70 kernel/kcov.c:217 Code: 00 00 5b e9 12 a8 27 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 e8 9c 1a 12 <65> 8b 05 f9 9c 1a 12 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 RSP: 0018:ffffc90000a08d88 EFLAGS: 00000006 RAX: 0000000080010002 RBX: ffff88805ab03340 RCX: ffffffff89a74db4 RDX: ffff888028dea440 RSI: ffffffff89a74dc2 RDI: 0000000000000006 RBP: ffff888061147800 R08: 0000000000000006 R09: 1867f9e708000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1867f9e708000000 R13: 0000000000000000 R14: ffff888061147c00 R15: ffffffff89a74b80 FS: 00005555573e8500(0000) GS:ffff8881247bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 000000005bbca000 CR4: 00000000003526f0 Call Trace: should_restart_cycle net/sched/sch_taprio.c:874 [inline] advance_sched+0x242/0xc80 net/sched/sch_taprio.c:953 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 46 ca 01 f6 48 89 df e8 2e 1e 02 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 1b f2 f5 65 8b 05 1e 38 40 08 85 c0 74 16 5b RSP: 0018:ffffc90002fb7ca8 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff8880b8427c80 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8de4f0f5 RDI: ffffffff8c162400 RBP: 0000000000000283 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90ab3597 R11: 0000000000000000 R12: 0000000000000000 R13: 1bc16d53e45cbe0e R14: dffffc0000000000 R15: ffff8880b8427c80 clock_was_set+0x599/0x870 kernel/time/hrtimer.c:972 do_settimeofday64+0x35d/0x540 kernel/time/timekeeping.c:1454 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1132 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1116 [inline] __x64_sys_clock_settime+0x1be/0x2a0 kernel/time/posix-timers.c:1116 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1abc18ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff1d0e85f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f1abc3b5fa0 RCX: 00007f1abc18ebe9 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000 RBP: 00007f1abc211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1abc3b5fa0 R14: 00007f1abc3b5fa0 R15: 0000000000000002 rcu: rcu_preempt kthread starved for 10490 jiffies! g9569 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:28760 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 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: 44 Comm: kworker/u8:3 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xdfd/0x1600 kernel/smp.c:877 Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 05 05 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31 RSP: 0018:ffffc90000b47888 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853fe80 RCX: ffffffff81af8e41 RDX: ffff8880226d0000 RSI: ffffffff81af8e1b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed10170a7fd1 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555573e8808 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245