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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

write to 0xffff8881027fc118 of 8 bytes by task 26413 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_commit_write fs/buffer.c:2079 [inline]
 block_write_end+0x13d/0x260 fs/buffer.c:2158
 generic_write_end+0x5e/0x180 fs/buffer.c:2172
 ext4_da_write_end+0x59b/0x730 fs/ext4/inode.c:3116
 generic_perform_write+0x251/0x3e0 mm/filemap.c:3781
 ext4_buffered_write_iter+0x309/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2f4/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 aio_write+0x2b1/0x380 fs/aio.c:1578
 io_submit_one+0x86f/0x13b0 fs/aio.c:1880
 __do_sys_io_submit fs/aio.c:1939 [inline]
 __se_sys_io_submit+0x105/0x270 fs/aio.c:1909
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1909
 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 0xffff8881027fc118 of 8 bytes by task 26408 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 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_fdatawrite mm/filemap.c:439 [inline]
 filemap_flush+0x154/0x180 mm/filemap.c:466
 ext4_alloc_da_blocks+0x47/0xd0 fs/ext4/inode.c:3170
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 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: 0x0000000000d593d0 -> 0x0000000000d593e0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26408 Comm: syz-executor.3 Tainted: G        W         5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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