rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=fee/1/0x4000000000000000 softirq=174227/174229 fqs=3 (t=10500 jiffies g=322597 q=20) rcu: rcu_preempt kthread starved for 10493 jiffies! g322597 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:29080 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 0 CPU: 0 PID: 11421 Comm: syz-executor.2 Not tainted 5.9.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf 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.cold+0x5b3/0xccd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:lock_acquire+0x2bd/0xad0 kernel/locking/lockdep.c:5009 Code: 00 00 00 48 c7 40 08 00 00 00 00 48 8b 84 24 b8 00 00 00 65 48 2b 04 25 28 00 00 00 0f 85 ba 06 00 00 48 81 c4 c0 00 00 00 5b <5d> 41 5c 41 5d 41 5e 41 5f c3 65 8b 15 e2 25 a7 7e 83 fa 3f 0f 87 RSP: 0018:ffffc90000007c98 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffff8880498c8860 RCX: ffffffff815a14fb RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c5f3ab7 R10: fffffbfff18be756 R11: 0000000000000001 R12: 0000000000000000 R13: ffff8880498c88c8 R14: 0000000000000000 R15: ffff88803accc240 __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] mrp_periodic_timer+0x34/0x170 net/802/mrp.c:609 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x2de/0xa24 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+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x1f3/0x230 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline] RIP: 0010:__pv_queued_spin_lock_slowpath+0x3a5/0xaf0 kernel/locking/qspinlock.c:508 Code: eb c6 45 01 01 41 bc 00 80 00 00 48 c1 e9 03 83 e3 07 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 2c 01 eb 0c f3 90 <41> 83 ec 01 0f 84 65 04 00 00 41 0f b6 45 00 38 d8 7f 08 84 c0 0f RSP: 0018:ffffc9001833f370 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1ffff11042825050 RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffff888214128282 RBP: ffff888214128280 R08: 0000000000000001 R09: ffff888214128283 R10: ffffed1042825050 R11: 0000000000000001 R12: 0000000000004f02 R13: ffffed1042825050 R14: 0000000000000001 R15: ffff8880ae636b80 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:656 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113 spin_lock include/linux/spinlock.h:354 [inline] ext4_lock_group+0x1e5/0x240 fs/ext4/ext4.h:3232 ext4_mb_find_by_goal+0x2cb/0xd80 fs/ext4/mballoc.c:1905 ext4_mb_regular_allocator+0x237/0x2090 fs/ext4/mballoc.c:2324 ext4_mb_new_blocks+0x1da1/0x4730 fs/ext4/mballoc.c:4920 ext4_ext_map_blocks+0x2320/0x61b0 fs/ext4/extents.c:4238 ext4_map_blocks+0x7b8/0x1650 fs/ext4/inode.c:625 ext4_alloc_file_blocks.isra.0+0x2ef/0xac0 fs/ext4/extents.c:4427 ext4_fallocate+0x403/0x3f20 fs/ext4/extents.c:4696 vfs_fallocate+0x48d/0x9d0 fs/open.c:309 ksys_fallocate fs/open.c:332 [inline] __do_sys_fallocate fs/open.c:340 [inline] __se_sys_fallocate fs/open.c:338 [inline] __x64_sys_fallocate+0xcf/0x140 fs/open.c:338 do_syscall_64+0x2d/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:00007fdfea34bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002e40 RCX: 000000000045d579 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000010000101 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fff040c7b9f R14: 00007fdfea34c9c0 R15: 000000000118cf4c