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

write to 0xffff88821aa48a04 of 4 bytes by interrupt on cpu 1:
 calc_wb_limits.part.0+0x7b/0xb0 block/blk-wbt.c:304
 calc_wb_limits block/blk-wbt.c:298 [inline]
 scale_up block/blk-wbt.c:313 [inline]
 scale_up+0x7f/0x250 block/blk-wbt.c:309
 wb_timer_fn+0x2cd/0xad0 block/blk-wbt.c:393
 blk_stat_timer_fn+0x3b0/0x3d0 block/blk-stat.c:99
 call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0xc0c/0xcd0 kernel/time/timer.c:1786
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 compound_head include/linux/page-flags.h:174 [inline]
 PageSwapBacked include/linux/page-flags.h:340 [inline]
 mm_counter_file include/linux/mm.h:1657 [inline]
 mm_counter include/linux/mm.h:1666 [inline]
 copy_one_pte mm/memory.c:792 [inline]
 copy_pte_range mm/memory.c:841 [inline]
 copy_pmd_range mm/memory.c:892 [inline]
 copy_pud_range mm/memory.c:926 [inline]
 copy_p4d_range mm/memory.c:948 [inline]
 copy_page_range+0xf7f/0x19b0 mm/memory.c:1010
 dup_mmap kernel/fork.c:604 [inline]
 dup_mm+0x74a/0xba0 kernel/fork.c:1360
 copy_mm kernel/fork.c:1416 [inline]
 copy_process+0x3138/0x3c40 kernel/fork.c:2072
 _do_fork+0xfe/0x7a0 kernel/fork.c:2421
 __do_sys_clone kernel/fork.c:2576 [inline]
 __se_sys_clone kernel/fork.c:2557 [inline]
 __x64_sys_clone+0x130/0x170 kernel/fork.c:2557
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88821aa48a04 of 4 bytes by task 11666 on cpu 0:
 rwb_enabled block/blk-wbt.c:80 [inline]
 bio_to_wbt_flags block/blk-wbt.c:551 [inline]
 wbt_track+0x39/0xa0 block/blk-wbt.c:600
 __rq_qos_track+0x52/0x80 block/blk-rq-qos.c:81
 rq_qos_track block/blk-rq-qos.h:189 [inline]
 blk_mq_make_request+0x32e/0xf60 block/blk-mq.c:1945
 generic_make_request block/blk-core.c:1066 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1008
 submit_bio+0x96/0x3c0 block/blk-core.c:1192
 submit_bh_wbc+0x40f/0x460 fs/buffer.c:3135
 __block_write_full_page+0x4e9/0x870 fs/buffer.c:1807
 block_write_full_page+0x1c0/0x1e0 fs/buffer.c:2993
 blkdev_writepage+0x2e/0x40 fs/block_dev.c:609
 __writepage+0x40/0xb0 mm/page-writeback.c:2303
 write_cache_pages+0x47a/0xb40 mm/page-writeback.c:2238
 generic_writepages mm/page-writeback.c:2329 [inline]
 generic_writepages+0x79/0xc0 mm/page-writeback.c:2318
 blkdev_writepages+0x27/0x40 fs/block_dev.c:2060
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1c5/0x230 mm/filemap.c:421
 file_write_and_wait_range+0xfd/0x160 mm/filemap.c:782
 blkdev_fsync+0x50/0xb0 fs/block_dev.c:666
 vfs_fsync_range+0x82/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2856 [inline]
 blkdev_write_iter fs/block_dev.c:2021 [inline]
 blkdev_write_iter+0x258/0x2b0 fs/block_dev.c:1993
 call_write_iter include/linux/fs.h:1902 [inline]
 do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x13b/0x3c0 fs/read_write.c:951
 vfs_iter_write+0x5c/0x80 fs/read_write.c:983
 iter_file_splice_write+0x530/0x840 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0xa0/0xc0 fs/splice.c:1037
 splice_direct_to_actor+0x22b/0x540 fs/splice.c:992
 do_splice_direct+0x161/0x1e0 fs/splice.c:1080
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x12a/0x140 fs/read_write.c:1511
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11666 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================