rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=a12c/1/0x4000000000000000 softirq=67085/67086 fqs=1 (detected by 0, t=10506 jiffies, g=101973, q=33 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9542 Comm: kworker/u4:8 Not tainted 6.0.0-rc1-syzkaller-00160-g4c2d0b039c5c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Workqueue: bat_events batadv_nc_worker RIP: 0010:rb_link_node include/linux/rbtree.h:62 [inline] RIP: 0010:rb_add_cached include/linux/rbtree.h:182 [inline] RIP: 0010:timerqueue_add+0x1ea/0x330 lib/timerqueue.c:40 Code: f0 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 e8 3b bb 59 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 f9 00 00 00 48 8d 7d 08 48 c7 45 00 00 00 00 00 48 b8 00 00 RSP: 0018:ffffc900001e0dd0 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff11003a57a68 RSI: ffffffff84225015 RDI: 0000000000000006 RBP: ffff88801d2bd340 R08: 0000000000000006 R09: ffff88801d2bd340 R10: ffff88801d2bd340 R11: 0000000000000000 R12: ffff8880b9b2a540 R13: 0000000000000000 R14: ffff8880b9b2a540 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f408fb09104 CR3: 0000000040939000 CR4: 0000000000350ee0 Call Trace: enqueue_hrtimer+0x171/0x3e0 kernel/time/hrtimer.c:1091 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xaf3/0xe40 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:__rcu_read_unlock+0xc0/0x570 kernel/rcu/tree_plugin.h:423 Code: 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e b6 01 00 00 8b 85 40 04 00 00 <85> c0 75 54 65 48 8b 1c 25 80 6f 02 00 48 8d bb 3c 04 00 00 48 b8 RSP: 0018:ffffc90014a47be8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff110045a27e8 RSI: ffffffff8918ed28 RDI: ffff888022d13f40 RBP: ffff888022d13b00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888022d13b00 R13: ffffffffffffffff R14: ffff888077a10c80 R15: 000000000000006a rcu_read_unlock include/linux/rcupdate.h:738 [inline] batadv_nc_process_nc_paths.part.0+0x21d/0x3c0 net/batman-adv/network-coding.c:699 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:679 [inline] batadv_nc_worker+0xce4/0xfa0 net/batman-adv/network-coding.c:735 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 rcu: rcu_preempt kthread starved for 10500 jiffies! g101973 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:28440 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: 16712 Comm: kworker/u4:3 Not tainted 6.0.0-rc1-syzkaller-00160-g4c2d0b039c5c #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:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x60 kernel/kcov.c:200 Code: be a8 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 e9 63 86 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 80 6f 02 00 00 01 ff 00 74 0e 85 c9 74 35 8b 82 bc 15 00 00 85 c0 74 2b 8b RSP: 0018:ffffc9000a917940 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff8880b9b3edc0 RCX: 0000000000000000 RDX: ffff88807bed1d80 RSI: ffffffff81715b81 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed1017367db9 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000001 rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:414 [inline] smp_call_function_many_cond+0x5c1/0x1430 kernel/smp.c:988 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