rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=4ca4/1/0x4000000000000000 softirq=33295/33301 fqs=0 (detected by 0, t=10502 jiffies, g=45577, q=67 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12745 Comm: syz-executor.0 Not tainted 6.0.0-rc2-syzkaller-00283-g10d4879f9ef0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xc5/0x570 kernel/locking/lockdep.c:5637 Code: 08 00 00 00 48 89 d0 48 89 54 24 08 48 c1 e8 06 48 8d 3c c5 50 f5 dd 8d e8 c8 39 68 00 48 8b 54 24 08 48 0f a3 15 0b 4c 7f 0c <0f> 82 83 03 00 00 48 c7 c0 ec 28 de 8d 48 ba 00 00 00 00 00 fc ff RSP: 0018:ffffc900003f8c50 EFLAGS: 00000047 RAX: 0000000000000001 RBX: 1ffff9200007f18c RCX: ffffffff815ea938 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8dddf550 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8dddf557 R10: fffffbfff1bbbeaa R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff9134a528 R15: 0000000000000000 FS: 00007f96ec3dd700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002009e030 CR3: 000000007c7fa000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 debug_object_deactivate lib/debugobjects.c:732 [inline] debug_object_deactivate+0x101/0x300 lib/debugobjects.c:720 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate kernel/time/hrtimer.c:481 [inline] __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x3f3/0xe40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 9a 3c dc f7 48 89 ef e8 22 be dc f7 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 63 7f cf f7 65 8b 05 ac 0a 80 76 85 c0 74 0a 5b 5d c3 e8 d0 4c RSP: 0018:ffffc9000a367780 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff2123806 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff8880284ceec0 R08: 0000000000000001 R09: ffffffff908da9ef R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000010 R14: 0000000000000001 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline] __wake_up_common_lock+0xde/0x130 kernel/sched/wait.c:139 __unix_dgram_recvmsg+0x2cd/0xb80 net/unix/af_unix.c:2434 unix_dgram_recvmsg+0xc0/0xe0 net/unix/af_unix.c:2504 sock_recvmsg_nosec net/socket.c:995 [inline] ____sys_recvmsg+0x536/0x600 net/socket.c:2699 ___sys_recvmsg+0xf2/0x180 net/socket.c:2743 do_recvmmsg+0x25e/0x6e0 net/socket.c:2837 __sys_recvmmsg net/socket.c:2916 [inline] __do_sys_recvmmsg net/socket.c:2939 [inline] __se_sys_recvmmsg net/socket.c:2932 [inline] __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2932 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f96ed489279 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f96ec3dd168 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f96ed59c050 RCX: 00007f96ed489279 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007f96ed4e3189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffefbf51dcf R14: 00007f96ec3dd300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10502 jiffies! g45577 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:28928 pid: 16 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5182 [inline] __schedule+0xadf/0x52b0 kernel/sched/core.c:6494 schedule+0xda/0x1b0 kernel/sched/core.c:6570 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x190/0x910 kernel/rcu/tree.c:1657 rcu_gp_kthread+0x236/0x360 kernel/rcu/tree.c:1854 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 7121 Comm: kworker/u4:12 Not tainted 6.0.0-rc2-syzkaller-00283-g10d4879f9ef0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Workqueue: events_unbound toggle_allocation_gate Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x46/0x14f lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x206/0x250 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:514 print_other_cpu_stall kernel/rcu/tree_stall.h:619 [inline] check_cpu_stall kernel/rcu/tree_stall.h:762 [inline] rcu_pending kernel/rcu/tree.c:3660 [inline] rcu_sched_clock_irq+0x2404/0x2530 kernel/rcu/tree.c:2342 update_process_times+0x11a/0x1a0 kernel/time/timer.c:1839 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243 tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1480 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:csd_lock_wait kernel/smp.c:414 [inline] RIP: 0010:smp_call_function_many_cond+0x5c8/0x1430 kernel/smp.c:988 Code: 0a 00 85 ed 74 48 48 8b 44 24 08 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 7f b4 0a 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 b5 0b 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0018:ffffc9000522f948 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b9b3f7a0 RCX: 0000000000000000 RDX: ffff8880791f6040 RSI: ffffffff81708591 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed1017367ef5 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000001 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1154 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1302 [inline] text_poke_bp_batch+0x233/0x6c0 arch/x86/kernel/alternative.c:1490 text_poke_flush arch/x86/kernel/alternative.c:1660 [inline] text_poke_flush arch/x86/kernel/alternative.c:1657 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1667 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0x32f/0x410 kernel/jump_label.c:801 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:811 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:803 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306