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BUG: KCSAN: data-race in wbt_issue / wbt_issue

write to 0xffff88812a3cb828 of 8 bytes by task 10711 on cpu 0:
 wbt_issue block/blk-wbt.c:619 [inline]
 wbt_issue+0xd0/0xf0 block/blk-wbt.c:603
 __rq_qos_issue+0x4a/0x80 block/blk-rq-qos.c:54
 rq_qos_issue block/blk-rq-qos.h:162 [inline]
 blk_mq_start_request+0x32a/0x370 block/blk-mq.c:688
 loop_queue_rq+0x64/0x2b0 drivers/block/loop.c:1898
 blk_mq_dispatch_rq_list+0xbe9/0xe40 block/blk-mq.c:1273
 blk_mq_do_dispatch_sched+0x11d/0x260 block/blk-mq-sched.c:115
 blk_mq_sched_dispatch_requests+0x2b4/0x380 block/blk-mq-sched.c:211
 __blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1403
 __blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1471
 blk_mq_run_hw_queue+0x103/0x1c0 block/blk-mq.c:1508
 blk_mq_sched_insert_requests+0x1ca/0x2e0 block/blk-mq-sched.c:444
 blk_mq_flush_plug_list+0x572/0x6c0 block/blk-mq.c:1772
 blk_flush_plug_list+0x271/0x2a0 block/blk-core.c:1766
 blk_finish_plug block/blk-core.c:1783 [inline]
 blk_finish_plug+0x60/0x84 block/blk-core.c:1779

read to 0xffff88812a3cb828 of 8 bytes by task 10699 on cpu 1:
 wbt_issue block/blk-wbt.c:617 [inline]
 wbt_issue+0x8e/0xf0 block/blk-wbt.c:603
 __rq_qos_issue+0x4a/0x80 block/blk-rq-qos.c:54
 rq_qos_issue block/blk-rq-qos.h:162 [inline]
 blk_mq_start_request+0x32a/0x370 block/blk-mq.c:688
 loop_queue_rq+0x64/0x2b0 drivers/block/loop.c:1898
 blk_mq_dispatch_rq_list+0xbe9/0xe40 block/blk-mq.c:1273
 blk_mq_do_dispatch_sched+0x11d/0x260 block/blk-mq-sched.c:115
 blk_mq_sched_dispatch_requests+0x2b4/0x380 block/blk-mq-sched.c:211
 __blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1403
 __blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1471
 blk_mq_run_hw_queue+0x103/0x1c0 block/blk-mq.c:1508
 blk_mq_sched_insert_requests+0x1ca/0x2e0 block/blk-mq-sched.c:444
 blk_mq_flush_plug_list+0x572/0x6c0 block/blk-mq.c:1772
 blk_flush_plug_list+0x271/0x2a0 block/blk-core.c:1766

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10699 Comm: syz-executor.1 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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