rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5729/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=21821, q=1665 ncpus=2)
task:kworker/0:4     state:R  running task     stack:22208 pid:5729  tgid:5729  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f9/0x5500 kernel/sched/core.c:7197
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7521
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5947
Code: 19 00 00 b8 ff ff ff ff 65 0f c1 05 54 2d 47 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 1b c4 03 00 cc 90 0f 0b 90 48 c7
RSP: 0018:ffffc9000515f768 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000046
RDX: ffffea000078b290 RSI: ffffffff8d895ae3 RDI: ffffffff8ba87360
RBP: 00000000ffffffff R08: ffffffff8b2d39b0 R09: ffffffff8dfca240
R10: dffffc0000000000 R11: fffffbfff1f17027 R12: 0000000000000246
R13: ffff8880325dbd80 R14: ffff88813fe19358 R15: 0000000000000002
 lock_is_held include/linux/lockdep.h:249 [inline]
 remove_partial mm/slub.c:3545 [inline]
 get_partial_node_bulk mm/slub.c:3778 [inline]
 __refill_objects_node+0x12f/0x620 mm/slub.c:7071
 refill_objects+0x62/0x3d0 mm/slub.c:7213
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4665
 alloc_from_pcs mm/slub.c:4763 [inline]
 slab_alloc_node mm/slub.c:4897 [inline]
 __do_kmalloc_node mm/slub.c:5308 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5322
 _kmalloc_noprof include/linux/slab.h:971 [inline]
 usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
 ath9k_hif_usb_alloc_reg_in_urbs drivers/net/wireless/ath/ath9k/hif_usb.c:982 [inline]
 ath9k_hif_usb_alloc_urbs+0xbb1/0x1130 drivers/net/wireless/ath/ath9k/hif_usb.c:1048
 ath9k_hif_usb_dev_init drivers/net/wireless/ath/ath9k/hif_usb.c:1134 [inline]
 ath9k_hif_usb_firmware_cb+0x127/0x4c0 drivers/net/wireless/ath/ath9k/hif_usb.c:1267
 request_firmware_work_func+0x103/0x2e0 drivers/base/firmware_loader/main.c:1164
 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
 process_scheduled_works kernel/workqueue.c:3401 [inline]
 worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>