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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

read-write to 0xffff888100f8f120 of 8 bytes by task 7115 on cpu 1:
 percpu_counter_add_batch+0xc9/0x140 lib/percpu_counter.c:96
 wb_stat_mod include/linux/backing-dev.h:66 [inline]
 folio_account_dirtied mm/page-writeback.c:2678 [inline]
 __folio_mark_dirty+0x28d/0x4e0 mm/page-writeback.c:2723
 mark_buffer_dirty+0x148/0x250 fs/buffer.c:1200
 __block_commit_write fs/buffer.c:2177 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2253
 ext4_da_do_write_end fs/ext4/inode.c:2955 [inline]
 ext4_da_write_end+0x1ad/0x860 fs/ext4/inode.c:3028
 generic_perform_write+0x276/0x410 mm/filemap.c:3985
 ext4_buffered_write_iter+0x1f6/0x380 fs/ext4/file.c:299
 ext4_file_write_iter+0x29f/0xe30
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x771/0x8e0 fs/read_write.c:590
 ksys_write+0xeb/0x1b0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

read to 0xffff888100f8f120 of 8 bytes by task 7120 on cpu 0:
 percpu_counter_read include/linux/percpu_counter.h:110 [inline]
 __wb_update_bandwidth+0x83/0x5d0 mm/page-writeback.c:1461
 wb_update_bandwidth mm/page-writeback.c:1489 [inline]
 do_writepages+0x443/0x480 mm/page-writeback.c:2638
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 filemap_write_and_wait_range+0xb6/0x1f0 mm/filemap.c:685
 kiocb_invalidate_pages+0x87/0x1e0 mm/filemap.c:2703
 __iomap_dio_rw+0x585/0x1090 fs/iomap/direct-io.c:639
 iomap_dio_rw+0x40/0x90 fs/iomap/direct-io.c:749
 ext4_dio_write_iter fs/ext4/file.c:577 [inline]
 ext4_file_write_iter+0xaa4/0xe30 fs/ext4/file.c:696
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x771/0x8e0 fs/read_write.c:590
 ksys_write+0xeb/0x1b0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

value changed: 0x000000000012cad0 -> 0x000000000012cae0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7120 Comm: syz-executor.4 Not tainted 6.9.0-rc1-syzkaller-00274-g486291a0e624 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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