rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=55fc/1/0x4000000000000000 softirq=163876/163878 fqs=2 rcu: (detected by 0, t=10506 jiffies, g=230641, q=144 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 20987 Comm: syz-executor.0 Not tainted 6.6.0-rc7-syzkaller-00039-g4f82870119a4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 RIP: 0010:lock_release+0x669/0x9d0 kernel/locking/lockdep.c:5777 Code: 27 08 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 e0 00 00 00 0f 85 34 03 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f <5d> c3 0f 0b e9 23 fa ff ff 0f 0b 48 c7 c7 20 a5 0a 8b e8 e0 a5 5e RSP: 0018:ffffc900001f0b50 EFLAGS: 00000046 RAX: 5179b4ea6ff76d00 RBX: ffffffff920a73b8 RCX: ffffc900001f0a03 RDX: 0000000000000001 RSI: ffffffff8b0ab6a0 RDI: ffffffff8b5986e0 RBP: ffffc900001f0b50 R08: ffffffff8e9969af R09: 1ffffffff1d32d35 R10: dffffc0000000000 R11: fffffbfff1d32d36 R12: dffffc0000000000 R13: 1ffff9200003e16c R14: ffffc900001f0b80 R15: 0000000000000046 FS: 0000555555c55480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0f19598000 CR3: 000000003ce03000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194 debug_object_activate+0x3c4/0x530 lib/debugobjects.c:745 debug_hrtimer_activate kernel/time/hrtimer.c:422 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x310 kernel/time/hrtimer.c:1087 __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0x6c0/0xd10 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1063 [inline] __sysvec_apic_timer_interrupt+0x104/0x390 arch/x86/kernel/apic/apic.c:1080 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1074 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:91 [inline] RIP: 0010:syscall_enter_from_user_mode+0x3b/0x230 kernel/entry/common.c:112 Code: 49 89 fe 48 8b 7c 24 30 e8 e2 fa ff ff 0f 1f 44 00 00 0f 1f 44 00 00 e8 73 cc c8 f6 e8 2e cc c8 f6 fb 65 4c 8b 3d 45 95 37 75 <49> 8b 6f 08 40 f6 c5 3f 0f 84 b5 00 00 00 40 f6 c5 20 74 17 4c 89 RSP: 0018:ffffc90012117ef8 EFLAGS: 00000282 RAX: 5179b4ea6ff76d00 RBX: 00000000000000e7 RCX: ffffffff91edc303 RDX: dffffc0000000000 RSI: ffffffff8b0aa520 RDI: ffffffff8b5986e0 RBP: ffffc90012117f48 R08: ffffffff8e9969af R09: 1ffffffff1d32d35 R10: dffffc0000000000 R11: fffffbfff1d32d36 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90012117f58 R15: ffff888039b85940 do_syscall_64+0x22/0xc0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f0f1947cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc869be8d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 00007f0f1947cae9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000001b30020000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 rcu: rcu_preempt kthread starved for 10495 jiffies! g230641 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:25872 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x196c/0x4af0 kernel/sched/core.c:6695 schedule+0xc3/0x180 kernel/sched/core.c:6771 schedule_timeout+0x1bd/0x300 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1613 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1812 kthread+0x2d3/0x370 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 27677 Comm: kworker/u4:2 Not tainted 6.6.0-rc7-syzkaller-00039-g4f82870119a4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:300 [inline] RIP: 0010:smp_call_function_many_cond+0x1805/0x2890 kernel/smp.c:844 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 b4 58 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 ef 54 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 d3 54 RSP: 0018:ffffc90004c4f720 EFLAGS: 00000293 RAX: ffffffff8182c88d RBX: 1ffff110173282cd RCX: ffff8880259c1dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90004c4f920 R08: ffffffff8182c85c R09: 1ffffffff20dc870 R10: dffffc0000000000 R11: fffffbfff20dc871 R12: dffffc0000000000 R13: ffff8880b9941668 R14: ffff8880b983d440 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f58e29dbd58 CR3: 000000000d130000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1012 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2006 [inline] text_poke_bp_batch+0x350/0xb20 arch/x86/kernel/alternative.c:2216 text_poke_flush arch/x86/kernel/alternative.c:2407 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2414 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x132/0x250 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:830 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0x90f/0x1400 kernel/workqueue.c:2703 worker_thread+0xa5f/0xff0 kernel/workqueue.c:2784 kthread+0x2d3/0x370 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304