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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

write to 0xffff888101d2f140 of 8 bytes by interrupt on cpu 1:
 percpu_counter_add_batch+0x9c/0xd0 lib/percpu_counter.c:91
 __add_wb_stat include/linux/backing-dev.h:70 [inline]
 inc_wb_stat include/linux/backing-dev.h:75 [inline]
 __wb_writeout_inc mm/page-writeback.c:592 [inline]
 test_clear_page_writeback+0x37c/0x600 mm/page-writeback.c:2789
 end_page_writeback+0xd7/0x1b0 mm/filemap.c:1603
 end_buffer_async_write+0x1b0/0x250 fs/buffer.c:375
 end_bio_bh_io_sync+0x6f/0x90 fs/buffer.c:3001
 bio_endio+0x2d4/0x300 block/bio.c:1494
 req_bio_endio block/blk-core.c:261 [inline]
 blk_update_request+0x435/0xa40 block/blk-core.c:1425
 blk_mq_end_request+0x22/0x50 block/blk-mq.c:565
 lo_complete_rq+0xca/0x170 drivers/block/loop.c:541
 blk_complete_reqs block/blk-mq.c:577 [inline]
 blk_done_softirq+0x69/0x90 block/blk-mq.c:582
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:920
 smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff888101d2f140 of 8 bytes by task 1120 on cpu 0:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __wb_update_bandwidth+0x9f/0x470 mm/page-writeback.c:1353
 wb_update_bandwidth mm/page-writeback.c:1380 [inline]
 do_writepages+0x391/0x3c0 mm/page-writeback.c:2379
 filemap_fdatawrite_wbc mm/filemap.c:400 [inline]
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 filemap_write_and_wait_range+0x238/0x3c0 mm/filemap.c:704
 filemap_write_and_wait include/linux/fs.h:2865 [inline]
 __sync_blockdev block/bdev.c:193 [inline]
 sync_blockdev+0x3e/0x50 block/bdev.c:202
 ext4_put_super+0x60c/0x910 fs/ext4/super.c:1238
 generic_shutdown_super+0xe1/0x230 fs/super.c:465
 kill_block_super+0x4a/0x90 fs/super.c:1395
 deactivate_locked_super+0x65/0xd0 fs/super.c:335
 deactivate_super+0x85/0x90 fs/super.c:366
 cleanup_mnt+0x267/0x2d0 fs/namespace.c:1137
 __cleanup_mnt+0x15/0x20 fs/namespace.c:1144
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000010 -> 0x0000000000000020

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1120 Comm: syz-executor.0 Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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