rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6815/1:b..l
	(detected by 0, t=10502 jiffies, g=29945, q=232 ncpus=2)
task:cmp             state:R  running task     stack:24352 pid:6815  ppid:6751   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x4/0x80 kernel/kcov.c:320
Code: 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 <65> 48 8b 0d f4 94 81 7e 65 8b 15 f5 94 81 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc9000c52f5e0 EFLAGS: 00000246
RAX: ffffffff8a0773b5 RBX: ffff88805d1eda06 RCX: 1ffff920018a5efb
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffffffffffff R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff2e0b09c R11: 1ffffffff2e0b09c R12: ffffc9000c52f7a0
R13: dffffc0000000000 R14: ffffc9000c52f7b8 R15: ffff88805538c600
 ma_is_root lib/maple_tree.c:337 [inline]
 mas_next_node+0xb5/0xb70 lib/maple_tree.c:4648
 mas_dfs_postorder lib/maple_tree.c:6761 [inline]
 mt_validate+0x384f/0x4c90 lib/maple_tree.c:7245
 validate_mm_mt+0xcd/0x420 mm/mmap.c:295
 validate_mm+0xcc/0x2b0 mm/mmap.c:332
 mmap_region+0x780/0x1c70 mm/mmap.c:2922
 do_mmap+0x958/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9bf3483242
RSP: 002b:00007ffd50bcd488 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f9bf3156000 RCX: 00007f9bf3483242
RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f9bf3156000
RBP: 0000000000000812 R08: 0000000000000003 R09: 000000000005f000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffd50bcd548
R13: 00007f9bf31626b0 R14: 00007ffd50bcd8c0 R15: 00000fffaa179a94
 </TASK>
rcu: rcu_preempt kthread starved for 9699 jiffies! g29945 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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741