syzbot

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BUG: KCSAN: data-race in calc_wb_limits.part.0 / wbt_issue

write to 0xffff88821a6e1c04 of 4 bytes by interrupt on cpu 0:
 calc_wb_limits.part.0+0x70/0xa0 block/blk-wbt.c:304
 calc_wb_limits block/blk-wbt.c:298 [inline]
 scale_up block/blk-wbt.c:313 [inline]
 scale_up+0x7d/0x250 block/blk-wbt.c:309
 wb_timer_fn+0x2d6/0xad0 block/blk-wbt.c:382
 blk_stat_timer_fn+0x3af/0x3d0 block/blk-stat.c:99
 call_timer_fn+0x58/0x2e0 kernel/time/timer.c:1405
 expire_timers kernel/time/timer.c:1450 [inline]
 __run_timers kernel/time/timer.c:1774 [inline]
 __run_timers kernel/time/timer.c:1741 [inline]
 run_timer_softirq+0xb14/0xbd0 kernel/time/timer.c:1787
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xb5/0xd0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0xe2/0x270 arch/x86/kernel/apic/apic.c:1140
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:759 [inline]
 console_unlock+0x903/0xb70 kernel/printk/printk.c:2506
 vprintk_emit+0x405/0x500 kernel/printk/printk.c:2021
 vprintk_default+0x2e/0x40 kernel/printk/printk.c:2048
 vprintk_func+0x81/0x13a kernel/printk/printk_safe.c:385
 printk+0x69/0x91 kernel/printk/printk.c:2081
 kauditd_printk_skb kernel/audit.c:533 [inline]
 kauditd_hold_skb.cold+0x21/0x26 kernel/audit.c:566
 kauditd_send_queue+0x1af/0x220 kernel/audit.c:729
 kauditd_thread+0x469/0x540 kernel/audit.c:855
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff88821a6e1c04 of 4 bytes by task 3439 on cpu 1:
 rwb_enabled block/blk-wbt.c:80 [inline]
 wbt_issue+0x33/0xf0 block/blk-wbt.c:607
 __rq_qos_issue+0x43/0x70 block/blk-rq-qos.c:54
 rq_qos_issue block/blk-rq-qos.h:159 [inline]
 blk_mq_start_request+0x310/0x360 block/blk-mq.c:662
 loop_queue_rq+0x5f/0x280 drivers/block/loop.c:1933
 blk_mq_dispatch_rq_list+0x9dc/0xe80 block/blk-mq.c:1263
 blk_mq_do_dispatch_sched+0x12b/0x270 block/blk-mq-sched.c:115
 blk_mq_sched_dispatch_requests+0x2b6/0x380 block/blk-mq-sched.c:211
 __blk_mq_run_hw_queue+0xb1/0x150 block/blk-mq.c:1389
 blk_mq_run_work_fn+0x50/0x60 block/blk-mq.c:1648
 process_one_work+0x424/0x930 kernel/workqueue.c:2268
 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2414
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3439 Comm: kworker/1:1H Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
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