rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4662/1:b..l
	(detected by 1, t=10502 jiffies, g=8585, q=64)
task:modprobe        state:R  running task     stack:27536 pid: 4662 ppid:  3095 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216
Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a <c3> 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d c4 3a 89 7e 65 8b
RSP: 0018:ffffc900032cf620 EFLAGS: 00000293
RAX: ffffffff81cf5bb9 RBX: ffff88801c712070 RCX: ffff88802a8f5940
RDX: 0000000000000000 RSI: 000000030d4b1c64 RDI: ffff88801c712070
RBP: 0000000000000003 R08: ffffc9000007c58f R09: 1ffff9200000f8b1
R10: dffffc0000000000 R11: fffff5200000f8b2 R12: 0000000000000003
R13: ffff88801c729de8 R14: ffff88801c712070 R15: ffff88801c712050
 read_word_at_a_time+0x9/0x20 include/asm-generic/rwonce.h:84
 dentry_string_cmp fs/dcache.c:201 [inline]
 dentry_cmp fs/dcache.c:253 [inline]
 __d_lookup_rcu+0x4c0/0x760 fs/dcache.c:2352
 lookup_fast+0x159/0x720 fs/namei.c:1594
 walk_component+0x81/0x460 fs/namei.c:1980
 link_path_walk+0x665/0xd70 fs/namei.c:-1
 path_openat+0x28d/0x2fa0 fs/namei.c:3746
 do_filp_open+0x1e2/0x410 fs/namei.c:3777
 do_sys_openat2+0x150/0x4b0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7623e660ba
RSP: 002b:00007ffe2bc13d88 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffe2bc13e00 RCX: 00007f7623e660ba
RDX: 0000000000080000 RSI: 00007ffe2bc13e00 RDI: 00000000ffffff9c
RBP: 00007ffe2bc13df0 R08: 00007ffe2bc13ff7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000001b
R13: 00007f7623e42050 R14: 00007ffe2bc14010 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10538 jiffies! g8585 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:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
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:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729