rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=49e/1/0x4000000000000000 softirq=307395/307397 fqs=12 (t=10500 jiffies g=541149 q=310) rcu: rcu_preempt kthread starved for 10475 jiffies! g541149 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:28896 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x979/0xce0 kernel/sched/core.c:4527 NMI backtrace for cpu 1 CPU: 1 PID: 17930 Comm: syz-executor.4 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1f0/0x31e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x199/0x2a0 kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq+0x1920/0x1eb0 kernel/rcu/tree.c:2519 update_process_times+0x130/0x1b0 kernel/time/timer.c:1710 tick_sched_handle kernel/time/tick-sched.c:176 [inline] tick_sched_timer+0x25e/0x410 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0xd0/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:765 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:787 [inline] RIP: 0010:lock_acquire+0x9f/0x730 kernel/locking/lockdep.c:5000 Code: 10 00 74 16 48 c7 c7 b0 17 4d 89 e8 db eb 5a 00 48 ba 00 00 00 00 00 fc ff df 48 83 3d 19 31 f3 07 00 0f 84 27 06 00 00 9c 58 <0f> 1f 44 00 00 48 89 44 24 10 48 c7 c0 c0 17 4d 89 48 c1 e8 03 80 RSP: 0018:ffffc90000da8cf0 EFLAGS: 00000286 RAX: 0000000000000286 RBX: 1ffff11035a7c564 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8881a24fe878 RBP: ffff8881ad3e2240 R08: 0000000000000001 R09: 0000000000000000 R10: fffffbfff131e246 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8881ad3e2b24 R14: ffff8881a24fe878 R15: 0000000000000000 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] garp_join_timer+0x1b/0x130 net/802/garp.c:405 call_timer_fn+0x91/0x160 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers+0x65e/0x830 kernel/time/timer.c:1755 run_timer_softirq+0x46/0x80 kernel/time/timer.c:1768 __do_softirq+0x236/0x66c kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x91/0xe0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu+0x1e1/0x1f0 kernel/softirq.c:423 irq_exit_rcu+0x5/0x10 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0xd5/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:ext4_find_dest_de+0x3de/0xb60 fs/ext4/namei.c:1954 Code: 24 08 0f 85 32 07 00 00 e8 af 8c 6b ff 43 0f b6 04 2e 84 c0 0f 85 3f 05 00 00 41 0f b6 6f 06 49 8d 7f 04 48 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 41 05 00 00 45 0f b7 77 04 42 0f b6 04 RSP: 0018:ffffc90030eff950 EFLAGS: 00000a07 RAX: 1ffff11036bf9e05 RBX: 1ffff11036bf9e05 RCX: 0000000000040000 RDX: ffffc90010e31000 RSI: 000000000000419a RDI: ffff8881b5fcf02c RBP: 000000000000000a R08: ffffffff81d91508 R09: fffff520061dff4d R10: fffff520061dff4d R11: 0000000000000000 R12: ffffc90030effc70 R13: dffffc0000000000 R14: 1ffff11036bf9e05 R15: ffff8881b5fcf028 add_dirent_to_buf+0x308/0xab0 fs/ext4/namei.c:2012 ext4_add_entry+0x25bd/0x3f70 fs/ext4/namei.c:2253 ext4_mkdir+0xcbb/0x14c0 fs/ext4/namei.c:2815 vfs_mkdir+0x42a/0x600 fs/namei.c:3649 do_mkdirat+0x1b9/0x310 fs/namei.c:3672 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d579 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff7fd6e2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 0000000000020980 RCX: 000000000045d579 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000 RBP: 000000000118cf78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe42fcf96f R14: 00007ff7fd6e39c0 R15: 000000000118cf4c