I am running this kernel '5.4.0-0.rc8.git0.2.fc32.x86_64' for about ten days.

Just now I got a crash. It is suspected to be bfq problem. Please kindly take a look. Thanks.

[12012.929834] Oops: 0000 [#1] SMP PTI
[12012.929890] CPU: 5 PID: 73394 Comm: kworker/u12:1 Kdump: loaded Tainted: P           OE     5.4.0-0.rc8.git0.2.fc32.x86_64 #1
[12012.930173] Hardware name: [Redacted]
[12012.930454] Workqueue: writeback wb_workfn (flush-253:7)
[12012.930730] RIP: 0010:__list_del_entry_valid+0x2d/0x4c
[12012.931008] Code: 4c 8b 47 08 48 b8 00 01 00 00 00 00 ad de 48 39 c2 0f 84 71 00 00 00 48 b8 22 01 00 00 00 00 ad de 49 39 c0 0f 84 91 00 00 00 <49> 8b 30 48 39 fe 0f 85 71 00 00 00 48 8b 52 08 48 39 f2 0f 85 56
[12012.931751] RSP: 0000:ffffb27c8ad77a48 EFLAGS: 00010017
[12012.932028] RAX: dead000000000122 RBX: ffff8d846ed4e950 RCX: 0000000000000000
[12012.932307] RDX: 0000000000000000 RSI: ffff8d846ed4e958 RDI: ffff8d819b275538
[12012.932587] RBP: ffff8d819b275498 R08: 0000000000000000 R09: 0000000000000003
[12012.932867] R10: 0000000000000002 R11: ffffb27c8ad77b00 R12: ffff8d819b275410
[12012.933148] R13: ffff8d8470b0b200 R14: ffff8d846ed4e910 R15: ffff8d8466d52000
[12012.933427] FS:  0000000000000000(0000) GS:ffff8d847fb40000(0000) knlGS:0000000000000000
[12012.933909] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[12012.934176] CR2: 0000000000000000 CR3: 0000002cdc2b8001 CR4: 00000000001606e0
[12012.934442] Call Trace:
[12012.934708]  bfq_idle_extract+0x52/0xb0
[12012.934972]  bfq_put_idle_entity+0x13/0x30
[12012.935237]  bfq_bfqq_served+0xae/0x170
[12012.935502]  bfq_dispatch_request+0x3b3/0xea0
[12012.935768]  blk_mq_do_dispatch_sched+0xc6/0x120
[12012.936033]  blk_mq_sched_dispatch_requests+0x111/0x160
[12012.936300]  __blk_mq_run_hw_queue+0x55/0x110
[12012.936564]  __blk_mq_delay_run_hw_queue+0x164/0x170
[12012.936827]  blk_mq_run_hw_queue+0x87/0x110
[12012.937091]  blk_mq_sched_insert_requests+0x70/0xf0
[12012.937357]  blk_mq_flush_plug_list+0x214/0x2b0
[12012.937623]  blk_flush_plug_list+0xec/0x110
[12012.937887]  blk_finish_plug+0x21/0x2e
[12012.938153]  wb_writeback+0x169/0x2f0
[12012.938418]  wb_workfn+0x355/0x450
[12012.938682]  process_one_work+0x1b0/0x350
[12012.939740]  ? kthread_park+0x90/0x90
[12012.940005]  ret_from_fork+0x35/0x40