rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P375/1:b..l (detected by 1, t=10502 jiffies, g=77645, q=273) task:kworker/u4:3 state:R running task stack:21616 pid: 375 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 preempt_schedule_notrace+0x14d/0x190 kernel/sched/core.c:6538 preempt_schedule_notrace_thunk+0x16/0x18 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline] trace_lock_acquire+0xb4/0x190 include/trace/events/lock.h:13 lock_acquire+0xa5/0x4d0 kernel/locking/lockdep.c:5596 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:267 rcu_read_lock include/linux/rcupdate.h:687 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline] batadv_nc_worker+0xc8/0x5b0 net/batman-adv/network-coding.c:721 process_one_work+0x853/0x1140 kernel/workqueue.c:2297 worker_thread+0xac1/0x1320 kernel/workqueue.c:2444 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: rcu_preempt kthread starved for 10497 jiffies! g77645 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:26544 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 25284 Comm: syz-executor.5 Not tainted 5.15.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2599 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:vcpu_enter_guest+0x67d5/0x9650 arch/x86/kvm/x86.c:9712 Code: 00 4c 89 ff e8 8c 81 12 00 48 c7 c7 00 7a 43 8a e8 70 c0 e8 08 65 4c 89 3d 30 06 f0 7e e8 c3 57 78 00 fb 49 8d 9f e0 20 00 00 <48> 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 b5 49 bd 00 RSP: 0018:ffffc9000c12f480 EFLAGS: 00000282 RAX: 8d2cf93f81833a00 RBX: ffff88807cd7a0e0 RCX: ffffffff8165c2f1 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c12fb88 R08: dffffc0000000000 R09: fffffbfff1fa37fd R10: fffffbfff1fa37fd R11: 0000000000000000 R12: dffffc0000000000 R13: 00000035c79ec19c R14: ffffc9000c12f5c0 R15: ffff88807cd78000 vcpu_run+0x4d3/0xe50 arch/x86/kvm/x86.c:9819 kvm_arch_vcpu_ioctl_run+0x5c0/0xdb0 arch/x86/kvm/x86.c:10051 kvm_vcpu_ioctl+0x894/0xe20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3779 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc5498bea39 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc546e34188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc5499d1f60 RCX: 00007fc5498bea39 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00007fc549918e8f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc914044cf R14: 00007fc546e34300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 00 4c 89 ff add %cl,-0x1(%rcx,%rcx,4) 4: e8 8c 81 12 00 callq 0x128195 9: 48 c7 c7 00 7a 43 8a mov $0xffffffff8a437a00,%rdi 10: e8 70 c0 e8 08 callq 0x8e8c085 15: 65 4c 89 3d 30 06 f0 mov %r15,%gs:0x7ef00630(%rip) # 0x7ef0064d 1c: 7e 1d: e8 c3 57 78 00 callq 0x7857e5 22: fb sti 23: 49 8d 9f e0 20 00 00 lea 0x20e0(%r15),%rbx * 2a: 48 89 d8 mov %rbx,%rax <-- trapping instruction 2d: 48 c1 e8 03 shr $0x3,%rax 31: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) 36: 74 08 je 0x40 38: 48 89 df mov %rbx,%rdi 3b: e8 b5 49 bd 00 callq 0xbd49f5