rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=0adc/1/0x4000000000000000 softirq=63046/63048 fqs=1 rcu: (detected by 0, t=10506 jiffies, g=63313, q=263 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18755 Comm: syz.1.5847 Not tainted 6.14.0-rc6-syzkaller-00016-g0fed89a961ea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:hlock_class+0x0/0x130 kernel/locking/lockdep.c:225 Code: df e8 e4 49 87 00 e9 af fe ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> b8 00 00 00 00 00 fc ff df 53 48 89 fb 48 83 c7 20 48 89 fa 48 RSP: 0018:ffffc90000a28b40 EFLAGS: 00000002 RAX: 0000000000000003 RBX: 0000000000000000 RCX: ffffffff81967f12 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8880347e0af0 RBP: 0000000000000040 R08: 0000000000000000 R09: fffffbfff2dd9198 R10: ffffffff96ec8cc7 R11: 0000000000000001 R12: ffff8880347e0b11 R13: ffff8880347e0000 R14: 0000000000000003 R15: ffff8880347e0b18 FS: 00007fb3fa81b6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000400000000240 CR3: 0000000029256000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <IRQ> __lock_acquire+0x13a6/0x3c40 kernel/locking/lockdep.c:5224 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] advance_sched+0x67f/0xc60 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5816 Code: b8 ff ff ff ff 65 0f c1 05 10 ca 6b 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7 RSP: 0018:ffffc9000b6a7bc8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 1ffff920016d4f7a RCX: ffffffff8195c6ae RDX: 0000000000000001 RSI: ffffffff8b6cff80 RDI: ffffffff8bd36a20 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dd9198 R10: ffffffff96ec8cc7 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e061050 R14: 0000000000000000 R15: 0000000000000000 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x160 kernel/cpu.c:490 clock_was_set+0x11a/0x850 kernel/time/hrtimer.c:974 do_settimeofday64+0x305/0x4c0 kernel/time/timekeeping.c:1381 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1135 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1119 [inline] __x64_sys_clock_settime+0x1bf/0x2a0 kernel/time/posix-timers.c:1119 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb3f998d169 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:00007fb3fa81b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fb3f9ba5fa0 RCX: 00007fb3f998d169 RDX: 0000000000000000 RSI: 0000400000000240 RDI: 0000000000000000 RBP: 00007fb3f9a0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb3f9ba5fa0 R15: 00007ffc3835bac8 </TASK> rcu: rcu_preempt kthread starved for 10500 jiffies! g63313 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:27456 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 12901 Comm: kworker/u8:11 Not tainted 6.14.0-rc6-syzkaller-00016-g0fed89a961ea #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x4c6/0x12c0 kernel/smp.c:885 Code: 0c 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 ac 0e 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 e8 0b 00 00 8b 43 08 31 RSP: 0018:ffffc9001babf928 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8744a80 RCX: ffffffff81ade25a RDX: ffff888025e6a440 RSI: ffffffff81ade234 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000006 R12: ffffed10170e8951 R13: 0000000000000001 R14: ffff8880b863fe80 R15: ffff8880b8744a88 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000400000001000 CR3: 000000000df80000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> </IRQ> <TASK> on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2118 [inline] text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2328 text_poke_flush arch/x86/kernel/alternative.c:2519 [inline] text_poke_flush arch/x86/kernel/alternative.c:2516 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2526 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1d7/0x400 kernel/jump_label.c:920 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+0xfc/0x260 mm/kfence/core.c:842 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK>