rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5084/1:b..l P17452/1:b..l P15855/1:b..l rcu: (detected by 1, t=10502 jiffies, g=132553, q=29 ncpus=2) task:kworker/u4:4 state:R running task stack:28320 pid:15855 tgid:15855 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7008 irqentry_exit+0x36/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:lock_acquire+0x1ef/0x520 kernel/locking/lockdep.c:5722 Code: c1 05 4d 92 9b 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc9000db67ac8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92001b6cf5b RCX: 00000000cdecf8c2 RDX: 0000000000000001 RSI: ffffffff8acca220 RDI: ffffffff8b2ed4a0 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff23e21d0 R10: ffffffff91f10e87 R11: 0000000000000002 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8cfa7d60 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:301 [inline] rcu_read_lock include/linux/rcupdate.h:747 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x16e/0x10e0 net/batman-adv/network-coding.c:719 process_one_work+0x886/0x15d0 kernel/workqueue.c:2627 process_scheduled_works kernel/workqueue.c:2700 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2781 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 task:syz-executor.2 state:R running task stack:27856 pid:17452 tgid:17452 ppid:5091 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7008 irqentry_exit+0x36/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:__page_table_check_zero+0x1fe/0x5e0 mm/page_table_check.c:145 Code: df e8 96 7f f5 ff 48 89 d8 48 c1 e8 03 42 0f b6 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 55 03 00 00 44 8b 33 <31> ff 44 89 f6 e8 e8 8d 9f ff 45 85 f6 0f 85 ed 01 00 00 e8 6a 92 RSP: 0018:ffffc900123a7950 EFLAGS: 00000246 RAX: 0000000000000003 RBX: ffff8880159f5a90 RCX: ffffffff81e6d25a RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880159f5a90 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffed1002b3eb52 R10: ffff8880159f5a93 R11: 0000000000000001 R12: ffff8880159f5a50 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1138 [inline] free_unref_page_prepare+0x4ea/0xaa0 mm/page_alloc.c:2347 free_unref_page_list+0xe6/0xb40 mm/page_alloc.c:2533 release_pages+0x32a/0x14f0 mm/swap.c:1042 tlb_batch_pages_flush+0x9a/0x190 mm/mmu_gather.c:98 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline] tlb_flush_mmu mm/mmu_gather.c:300 [inline] tlb_finish_mmu+0x14b/0x6f0 mm/mmu_gather.c:392 exit_mmap+0x38b/0xa70 mm/mmap.c:3321 __mmput+0x12a/0x4d0 kernel/fork.c:1349 mmput+0x62/0x70 kernel/fork.c:1371 exit_mm kernel/exit.c:567 [inline] do_exit+0x9a5/0x2ad0 kernel/exit.c:856 do_group_exit+0xd4/0x2a0 kernel/exit.c:1018 __do_sys_exit_group kernel/exit.c:1029 [inline] __se_sys_exit_group kernel/exit.c:1027 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1027 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f501e87cce9 RSP: 002b:00007ffead0271d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000001e RCX: 00007f501e87cce9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 00000000000000d5 R09: 0000000000000000 R10: 0000001b31320000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 task:syz-executor.1 state:R running task stack:22784 pid:5084 tgid:5084 ppid:5072 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6865 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1115 [inline] copy_pmd_range mm/memory.c:1176 [inline] copy_pud_range mm/memory.c:1213 [inline] copy_p4d_range mm/memory.c:1237 [inline] copy_page_range+0x12c1/0x3c40 mm/memory.c:1335 dup_mmap+0x13da/0x1d90 kernel/fork.c:758 dup_mm kernel/fork.c:1691 [inline] copy_mm kernel/fork.c:1740 [inline] copy_process+0x43c8/0x73f0 kernel/fork.c:2502 kernel_clone+0xfd/0x930 kernel/fork.c:2907 __do_sys_clone+0xba/0x100 kernel/fork.c:3050 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f6007c79d13 RSP: 002b:00007fff0d42d1d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6007c79d13 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000555555de5750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 rcu: rcu_preempt kthread starved for 10236 jiffies! g132553 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:28336 pid:16 tgid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 __schedule_loop kernel/sched/core.c:6763 [inline] schedule+0xe9/0x270 kernel/sched/core.c:6778 schedule_timeout+0x137/0x290 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631 rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 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:86 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:112