==================================================================
BUG: KCSAN: data-race in filemap_write_and_wait_range / xas_set_mark

write to 0xffff88812cd7596c of 4 bytes by task 4657 on cpu 0:
 xa_mark_set lib/xarray.c:69 [inline]
 xas_set_mark+0x13e/0x150 lib/xarray.c:889
 tag_pages_for_writeback+0x9d/0x2e0 mm/page-writeback.c:2124
 ext4_writepages+0x683/0x1d10 fs/ext4/inode.c:2740
 do_writepages+0x7b/0x150 mm/page-writeback.c:2352
 __filemap_fdatawrite_range mm/filemap.c:424 [inline]
 filemap_write_and_wait_range+0x20a/0x390 mm/filemap.c:657
 __iomap_dio_rw+0x40a/0xa10 fs/iomap/direct-io.c:525
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:641
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x21a/0x290 fs/ext4/file.c:128
 call_read_iter include/linux/fs.h:1971 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812cd7596c of 4 bytes by task 4655 on cpu 1:
 xa_marked include/linux/xarray.h:418 [inline]
 mapping_tagged include/linux/fs.h:490 [inline]
 __filemap_fdatawrite_range mm/filemap.c:420 [inline]
 filemap_write_and_wait_range+0x1d8/0x390 mm/filemap.c:657
 __iomap_dio_rw+0x40a/0xa10 fs/iomap/direct-io.c:525
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:641
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x21a/0x290 fs/ext4/file.c:128
 call_read_iter include/linux/fs.h:1971 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4655 Comm: syz-executor.2 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================