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

read-write to 0xffff888106a79b40 of 8 bytes by task 25646 on cpu 0:
 instrument_read_write include/linux/instrumented.h:55 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:99 [inline]
 node_set_mark lib/xarray.c:95 [inline]
 xas_set_mark lib/xarray.c:885 [inline]
 __xa_set_mark+0xdb/0x1b0 lib/xarray.c:1910
 __folio_mark_dirty+0x3c3/0x4e0 mm/page-writeback.c:2670
 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:3941
 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+0x6d/0x75

read to 0xffff888106a79b40 of 8 bytes by task 25647 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1723 [inline]
 xas_find_marked+0x216/0x660 lib/xarray.c:1354
 find_get_entry+0x5d/0x290 mm/filemap.c:1970
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2220
 mpage_prepare_extent_to_map+0x321/0xb70 fs/ext4/inode.c:2392
 ext4_do_writepages+0xa20/0x2100 fs/ext4/inode.c:2677
 ext4_writepages+0x15f/0x2f0 fs/ext4/inode.c:2768
 do_writepages+0x1c6/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 __filemap_fdatawrite mm/filemap.c:436 [inline]
 filemap_flush+0x95/0xc0 mm/filemap.c:463
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3072
 __ext4_ioctl fs/ext4/ioctl.c:1424 [inline]
 ext4_ioctl+0xff0/0x2dc0 fs/ext4/ioctl.c:1627
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0xd3/0x150 fs/ioctl.c:890
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:890
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x07ffffffffffffff -> 0x1fffffffffffffff

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25647 Comm: syz-executor.2 Tainted: G        W          6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================