rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P431/1:b..l P4309/1:b..l (detected by 0, t=10502 jiffies, g=6145, q=87) task:syz-executor.1 state:R running task stack: 0 pid: 4309 ppid: 3996 flags:0x00000004 Call trace: __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518 context_switch kernel/sched/core.c:5030 [inline] __schedule+0xf10/0x1e48 kernel/sched/core.c:6376 preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6780 arm64_preempt_schedule_irq+0x174/0x2c4 arch/arm64/kernel/entry-common.c:260 el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] count_memcg_events include/linux/memcontrol.h:1058 [inline] count_memcg_event_mm+0x1d0/0x308 include/linux/memcontrol.h:1081 handle_mm_fault+0x1c4/0x3424 mm/memory.c:4834 __do_page_fault arch/arm64/mm/fault.c:505 [inline] do_page_fault+0x700/0xb60 arch/arm64/mm/fault.c:605 do_mem_abort+0x70/0x1d8 arch/arm64/mm/fault.c:819 el0_da+0x94/0x20c arch/arm64/kernel/entry-common.c:494 el0t_64_sync_handler+0xc0/0xe4 arch/arm64/kernel/entry-common.c:629 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584 task:kworker/u4:4 state:R running task stack: 0 pid: 431 ppid: 2 flags:0x00000008 Workqueue: writeback wb_workfn (flush-259:0) Call trace: __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518 context_switch kernel/sched/core.c:5030 [inline] __schedule+0xf10/0x1e48 kernel/sched/core.c:6376 preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6780 arm64_preempt_schedule_irq+0x174/0x2c4 arch/arm64/kernel/entry-common.c:260 el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] mod_lruvec_page_state include/linux/vmstat.h:497 [inline] inc_lruvec_page_state include/linux/vmstat.h:549 [inline] __test_set_page_writeback+0x96c/0xc70 mm/page-writeback.c:2864 ext4_bio_write_page+0x21c/0x1c3c mpage_submit_page fs/ext4/inode.c:2101 [inline] mpage_map_and_submit_buffers fs/ext4/inode.c:2349 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2488 [inline] ext4_writepages+0x1b90/0x36fc fs/ext4/inode.c:2817 do_writepages+0x39c/0x5ec mm/page-writeback.c:2364 __writeback_single_inode+0x148/0x13a4 fs/fs-writeback.c:1647 writeback_sb_inodes+0x94c/0x1654 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x110/0x39c fs/fs-writeback.c:2001 wb_writeback+0x410/0xfc8 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xbb4/0x1070 fs/fs-writeback.c:2288 process_one_work+0x790/0x11b8 kernel/workqueue.c:2310 worker_thread+0x910/0x1034 kernel/workqueue.c:2457 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 rcu: rcu_preempt kthread starved for 10507 jiffies! g6145 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: 0 pid: 15 ppid: 2 flags:0x00000008 Call trace: __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518 context_switch kernel/sched/core.c:5030 [inline] __schedule+0xf10/0x1e48 kernel/sched/core.c:6376 schedule+0x11c/0x1c8 kernel/sched/core.c:6459 schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x26c/0x13d4 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xc4/0x2c4 kernel/rcu/tree.c:2145 kthread+0x37c/0x45c kernel/kthread.c:334 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:syz-executor.4 state:R running task stack: 0 pid: 4301 ppid: 3999 flags:0x00000000 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 sched_show_task+0x43c/0x574 kernel/sched/core.c:8640 dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10914 rcu_check_gp_kthread_starvation+0x1f0/0x254 kernel/rcu/tree_stall.h:488 print_other_cpu_stall+0x202c/0x2290 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0x1894/0x1b8c kernel/rcu/tree.c:2619 update_process_times+0x1d4/0x270 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1686 [inline] __hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1750 hrtimer_interrupt+0x2c0/0xb64 kernel/time/hrtimer.c:1812 timer_handler drivers/clocksource/arm_arch_timer.c:659 [inline] arch_timer_handler_virt+0x74/0x88 drivers/clocksource/arm_arch_timer.c:670 handle_percpu_devid_irq+0x29c/0x7fc kernel/irq/chip.c:933 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq_desc kernel/irq/irqdesc.c:651 [inline] handle_domain_irq+0xec/0x178 kernel/irq/irqdesc.c:706 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:758 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899 do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522 local_daif_restore arch/arm64/include/asm/daifflags.h:117 [inline] el0_svc_common+0xa8/0x258 arch/arm64/kernel/syscall.c:107 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584