syzbot

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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

write to 0xffff888102b05d18 of 8 bytes by task 8402 on cpu 0:
 percpu_counter_add_batch+0xb4/0x130 lib/percpu_counter.c:91
 wb_stat_mod include/linux/backing-dev.h:70 [inline]
 folio_account_dirtied+0x1d9/0x300 mm/page-writeback.c:2466
 __folio_mark_dirty+0x8e/0x130 mm/page-writeback.c:2509
 __set_page_dirty include/linux/pagemap.h:867 [inline]
 mark_buffer_dirty+0x14f/0x260 fs/buffer.c:1108
 __block_commit_write fs/buffer.c:2083 [inline]
 block_write_end+0x13d/0x260 fs/buffer.c:2162
 generic_write_end+0x5e/0x180 fs/buffer.c:2176
 ext4_da_write_end+0x4de/0x630 fs/ext4/inode.c:3059
 generic_perform_write+0x261/0x400 mm/filemap.c:3767
 ext4_buffered_write_iter+0x25b/0x380 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2162 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 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+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888102b05d18 of 8 bytes by task 8390 on cpu 1:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __wb_update_bandwidth+0x87/0x420 mm/page-writeback.c:1352
 wb_update_bandwidth mm/page-writeback.c:1380 [inline]
 do_writepages+0x306/0x330 mm/page-writeback.c:2386
 filemap_fdatawrite_wbc mm/filemap.c:407 [inline]
 __filemap_fdatawrite_range mm/filemap.c:440 [inline]
 file_write_and_wait_range+0x132/0x1d0 mm/filemap.c:824
 ext4_sync_file+0x105/0x6e0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:182
 generic_write_sync include/linux/fs.h:2956 [inline]
 ext4_buffered_write_iter+0x322/0x380 fs/ext4/file.c:277
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2162 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 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+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1304 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000000ab2b0 -> 0x00000000000ab2c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8390 Comm: syz-executor.4 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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