syzbot

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

write to 0xffff888135d62d0c of 4 bytes by task 29744 on cpu 0:
 xa_mark_set lib/xarray.c:69 [inline]
 xas_set_mark+0x11e/0x130 lib/xarray.c:893
 __folio_start_writeback+0x2bf/0x5d0 mm/page-writeback.c:2858
 set_page_writeback+0x3d/0xe0 mm/folio-compat.c:78
 ext4_bio_write_page+0x119/0xb60 fs/ext4/page-io.c:451
 mpage_submit_page fs/ext4/inode.c:2102 [inline]
 mpage_process_page_bufs+0x431/0x530 fs/ext4/inode.c:2216
 mpage_prepare_extent_to_map+0x5b7/0xa50 fs/ext4/inode.c:2642
 ext4_writepages+0x6b2/0x1d00 fs/ext4/inode.c:2770
 do_writepages+0x1db/0x350 mm/page-writeback.c:2352
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0xd6/0x170 mm/filemap.c:779
 ext4_sync_file+0x105/0x6d0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2723 [inline]
 ext4_buffered_write_iter+0x2ec/0x330 fs/ext4/file.c:277
 ext4_file_write_iter+0x2e3/0x1210
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:852
 vfs_iter_write+0x4c/0x70 fs/read_write.c:893
 iter_file_splice_write+0x44a/0x7c0 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+0x345/0x660 fs/splice.c:891
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1305 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0xb9/0x150 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff888135d62d0c of 4 bytes by task 29759 on cpu 1:
 xa_marked include/linux/xarray.h:419 [inline]
 xas_find_marked+0x587/0x5e0 lib/xarray.c:1328
 find_get_entry mm/filemap.c:2032 [inline]
 find_get_pages_range_tag+0x103/0x480 mm/filemap.c:2314
 pagevec_lookup_range_tag+0x37/0x50 mm/swap.c:1122
 mpage_prepare_extent_to_map+0x1a4/0xa50 fs/ext4/inode.c:2577
 ext4_writepages+0x6b2/0x1d00 fs/ext4/inode.c:2770
 do_writepages+0x1db/0x350 mm/page-writeback.c:2352
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0xd6/0x170 mm/filemap.c:779
 ext4_sync_file+0x105/0x6d0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2723 [inline]
 ext4_buffered_write_iter+0x2ec/0x330 fs/ext4/file.c:277
 ext4_file_write_iter+0x2e3/0x1210
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:852
 vfs_iter_write+0x4c/0x70 fs/read_write.c:893
 iter_file_splice_write+0x44a/0x7c0 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+0x345/0x660 fs/splice.c:891
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x28000021 -> 0x10000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29759 Comm: syz-executor.2 Tainted: G        W         5.18.0-syzkaller-02752-gfdaf9a5840ac-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================