rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2925/1:b..l P11382/1:b..l rcu: (detected by 1, t=10502 jiffies, g=84433, q=309 ncpus=2) task:syz-executor state:R running task stack:21728 pid:11382 tgid:11382 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:227 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:239 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:562 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1105 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xd4/0x550 kernel/locking/lockdep.c:5730 Code: 8b 05 cc 08 94 7e 83 f8 08 0f 83 f4 02 00 00 89 c3 48 89 d8 48 c1 e8 06 48 8d 3c c5 e8 f7 17 90 be 08 00 00 00 e8 ec 03 8b 00 <48> 0f a3 1d 7c 29 a8 0e 73 16 e8 cd f5 09 00 84 c0 75 0d 80 3d a0 RSP: 0018:ffffc90004ad76a0 EFLAGS: 00000256 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff816fce64 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff9017f7e8 RBP: ffffc90004ad77f0 R08: ffffffff9017f7ef R09: 1ffffffff202fefd R10: dffffc0000000000 R11: fffffbfff202fefe R12: 1ffff9200095aedc R13: dffffc0000000000 R14: 0000000000000000 R15: ffffea000072e088 rcu_lock_acquire include/linux/rcupdate.h:326 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] page_ext_get+0x3d/0x2a0 mm/page_ext.c:525 __page_table_check_zero+0xb1/0x350 mm/page_table_check.c:148 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1095 [inline] free_unref_page+0xd36/0xea0 mm/page_alloc.c:2612 vfree+0x186/0x2e0 mm/vmalloc.c:3364 kcov_put kernel/kcov.c:438 [inline] kcov_close+0x2b/0x50 kernel/kcov.c:534 __fput+0x24c/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2f/0x27f0 kernel/exit.c:882 do_group_exit+0x207/0x2c0 kernel/exit.c:1031 get_signal+0x16a1/0x1740 kernel/signal.c:2917 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f846377895f RSP: 002b:00007ffe24eb7e50 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000003 RBX: 0000000000000005 RCX: 00007f846377895f RDX: 0000000000000003 RSI: 00007ffe24eb7ea0 RDI: 0000000000000005 RBP: 00007f84637e8a01 R08: 0000000000000000 R09: 00007ffe24eb7ca7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 00007ffe24eb7ea0 R14: 00007f8464444620 R15: 0000000000000003 task:kworker/u8:10 state:R running task stack:20912 pid:2925 tgid:2925 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x658/0xa30 kernel/locking/lockdep.c:5784 Code: 3c 3b 00 74 08 4c 89 f7 e8 15 d5 8a 00 f6 84 24 91 00 00 00 02 75 77 41 f7 c5 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 4b c7 44 27 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc90009c2f880 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92001385f22 RCX: ffffc90009c2f903 RDX: 0000000000000003 RSI: ffffffff8c0ae6c0 RDI: ffffffff8c606ec0 RBP: ffffc90009c2f9b0 R08: ffffffff9017f7ef R09: 1ffffffff202fefd R10: dffffc0000000000 R11: fffffbfff202fefe R12: 1ffff92001385f1c R13: 0000000000000246 R14: ffffc90009c2f910 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:336 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:771 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline] batadv_iv_ogm_schedule+0x6f3/0x10a0 net/batman-adv/bat_iv_ogm.c:868 batadv_iv_send_outstanding_bat_ogm_packet+0x6fe/0x810 net/batman-adv/bat_iv_ogm.c:1712 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10577 jiffies! g84433 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:26448 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111