==================================================================
BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

write to 0xffff88810281c518 of 8 bytes by task 13053 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]
 account_page_dirtied+0x1fe/0x2e0 mm/page-writeback.c:2458
 __set_page_dirty+0xbc/0x1a0 mm/page-writeback.c:2500
 mark_buffer_dirty+0x126/0x200 fs/buffer.c:1108
 __block_write_begin_int+0x8f8/0x1080 fs/buffer.c:2018
 __block_write_begin+0x2b/0x40 fs/buffer.c:2056
 ext4_da_write_begin+0x4a8/0x7f0 fs/ext4/inode.c:3024
 generic_perform_write+0x1b8/0x3e0 mm/filemap.c:3770
 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:729
 do_iter_write+0x192/0x5c0 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1314 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810281c518 of 8 bytes by task 8437 on cpu 0:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __wb_update_bandwidth+0x87/0x470 mm/page-writeback.c:1352
 wb_update_bandwidth+0x46/0x70 mm/page-writeback.c:1380
 wb_update_bandwidth_workfn+0x18/0x20 mm/backing-dev.c:279
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000044470 -> 0x0000000000044480

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8437 Comm: kworker/u4:6 Not tainted 5.15.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_update_bandwidth_workfn
==================================================================