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 1, t=10502 jiffies, g=260289, q=810 ncpus=2)
task:khugepaged      state:R  running task     stack:26264 pid:38    tgid:38    ppid:2      task_flags:0x200040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 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 e9 99 f8 03 00 cc cc cc cc cc
RSP: 0018:ffffc90000ae77b8 EFLAGS: 00010246
RAX: ffff888036028000 RBX: 1ffffffff1b73c85 RCX: 0000000000000fc0
RDX: 0000000000001000 RSI: ffff88805429e040 RDI: ffff888036028040
RBP: ffffc90000ae7ab0 R08: ffff88805429efff R09: 1ffff1100a853dff
R10: dffffc0000000000 R11: ffffed100a853e00 R12: fffa800000000000
R13: 0000000000000140 R14: fffa800036028000 R15: ffff88805429e000
 copy_mc_user_highpage include/linux/highmem.h:349 [inline]
 __collapse_huge_page_copy mm/khugepaged.c:811 [inline]
 collapse_huge_page mm/khugepaged.c:1214 [inline]
 hpage_collapse_scan_pmd+0x248f/0x3bc0 mm/khugepaged.c:1419
 khugepaged_scan_mm_slot mm/khugepaged.c:2454 [inline]
 khugepaged_do_scan mm/khugepaged.c:2541 [inline]
 khugepaged+0x986/0x1690 mm/khugepaged.c:2597
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>