rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P38/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=99881, q=522851 ncpus=2)
task:khugepaged      state:R  running task     stack:26440 pid:38    tgid:38    ppid:2      task_flags:0x200040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:copy_mc_enhanced_fast_string+0x6/0xf arch/x86/lib/copy_mc_64.S:130
Code: 89 ca e9 7d fd ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 89 f8 48 89 d1 <f3> a4 31 c0 c3 cc cc cc cc 48 89 c8 c3 cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90000af7858 EFLAGS: 00010246
RAX: ffff888043c8a000 RBX: 0000000000000450 RCX: 0000000000000fc0
RDX: 0000000000001000 RSI: ffff888010e8a040 RDI: ffff888043c8a040
RBP: ffffc90000af7b50 R08: ffff888010e8afff R09: 1ffff110021d15ff
R10: dffffc0000000000 R11: ffffed10021d1600 R12: ffff888010e8a000
R13: 000000000001275e R14: 1ffffffff1efb5d1 R15: ffff888043c8a000
 copy_mc_user_highpage include/linux/highmem.h:349 [inline]
 __collapse_huge_page_copy mm/khugepaged.c:824 [inline]
 collapse_huge_page mm/khugepaged.c:1227 [inline]
 hpage_collapse_scan_pmd+0x2389/0x3aa0 mm/khugepaged.c:1432
 khugepaged_scan_mm_slot mm/khugepaged.c:2461 [inline]
 khugepaged_do_scan mm/khugepaged.c:2548 [inline]
 khugepaged+0x986/0x1690 mm/khugepaged.c:2604
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>