rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=c3e/1/0x4000000000000000 softirq=23212/23212 fqs=0 (t=10501 jiffies g=32449 q=131) rcu: rcu_preempt kthread starved for 10502 jiffies! g32449 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:28888 pid: 13 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 schedule_timeout+0x148/0x250 kernel/time/timer.c:1878 rcu_gp_fqs_loop kernel/rcu/tree.c:1940 [inline] rcu_gp_kthread+0xbbe/0x1d70 kernel/rcu/tree.c:2113 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 NMI backtrace for cpu 0 CPU: 0 PID: 15669 Comm: syz-executor.5 Not tainted 5.11.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x1f4/0x230 kernel/rcu/tree_stall.h:337 print_cpu_stall kernel/rcu/tree_stall.h:569 [inline] check_cpu_stall kernel/rcu/tree_stall.h:643 [inline] rcu_pending kernel/rcu/tree.c:3751 [inline] rcu_sched_clock_irq.cold+0x48e/0xedf kernel/rcu/tree.c:2580 update_process_times+0x16d/0x200 kernel/time/timer.c:1782 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1369 __run_hrtimer kernel/time/hrtimer.c:1519 [inline] __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1583 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1645 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:91 [inline] sysvec_apic_timer_interrupt+0x48/0x100 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:629 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:199 Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 2e d7 5b f8 48 89 ef e8 d6 8b 5c f8 e8 81 b0 7b f8 fb bf 01 00 00 00 16 93 50 f8 65 8b 05 0f f9 04 77 85 c0 74 02 5d c3 e8 9b 4e 03 RSP: 0018:ffffc90000007e28 EFLAGS: 00000206 RAX: 0000000000d7493a RBX: ffffffff876c0d40 RCX: ffffffff81585217 RDX: 0000000000000000 RSI: 0000000000000103 RDI: 0000000000000001 RBP: ffff8880b9c24880 R08: 0000000000000001 R09: ffffffff8f866837 R10: fffffbfff1f0cd06 R11: 0000000000000000 R12: ffffc90000007eb8 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880b9c24880 expire_timers kernel/time/timer.c:1461 [inline] __run_timers.part.0+0x66c/0xa50 kernel/time/timer.c:1731 __run_timers kernel/time/timer.c:1712 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1744 __do_softirq+0x29b/0x9f6 kernel/softirq.c:343 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:226 [inline] __irq_exit_rcu kernel/softirq.c:420 [inline] irq_exit_rcu+0x134/0x200 kernel/softirq.c:432 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:629 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x25/0x50 kernel/locking/spinlock.c:191 Code: f8 5d c3 66 90 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 ea d6 5b f8 48 89 ef e8 92 8b 5c f8 f6 c7 02 75 1a 53 9d 01 00 00 00 e8 d1 92 50 f8 65 8b 05 ca f8 04 77 85 c0 74 0a 5b RSP: 0018:ffffc90001b8f590 EFLAGS: 00000246 RAX: 000000000001266d RBX: 0000000000000246 RCX: ffffffff81585217 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000 RBP: ffff888022a6e248 R08: 0000000000000001 R09: ffffffff8f866837 R10: fffffbfff1f0cd06 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline] __wake_up_common_lock+0xde/0x130 kernel/sched/wait.c:140 __jbd2_log_start_commit+0x21d/0x270 fs/jbd2/journal.c:507 jbd2_log_start_commit fs/jbd2/journal.c:526 [inline] jbd2_complete_transaction+0x1b6/0x200 fs/jbd2/journal.c:836 ext4_fc_commit+0x7e2/0x22a0 fs/ext4/fast_commit.c:1217 ext4_fsync_journal fs/ext4/fsync.c:115 [inline] ext4_sync_file+0x3cd/0xfe0 fs/ext4/fsync.c:174 vfs_fsync_range+0x13a/0x220 fs/sync.c:200 generic_write_sync include/linux/fs.h:2737 [inline] iomap_dio_complete+0x5f9/0x780 fs/iomap/direct-io.c:127 iomap_dio_rw+0x63/0x90 fs/iomap/direct-io.c:608 ext4_dio_write_iter fs/ext4/file.c:552 [inline] ext4_file_write_iter+0xe53/0x14d0 fs/ext4/file.c:662 call_write_iter include/linux/fs.h:1901 [inline] aio_write+0x350/0x7a0 fs/aio.c:1581 __io_submit_one fs/aio.c:1836 [inline] io_submit_one+0xde7/0x1b70 fs/aio.c:1883 __do_sys_io_submit fs/aio.c:1942 [inline] __se_sys_io_submit fs/aio.c:1912 [inline] __x64_sys_io_submit+0x18c/0x340 fs/aio.c:1912 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465b09 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:00007fda12ac2188 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000020000540 RSI: 000000000000003b RDI: 00007fda12a99000 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007fffde33ba1f R14: 00007fda12ac2300 R15: 0000000000022000