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

read-write to 0xffff88810624e470 of 8 bytes by task 3706 on cpu 1:
 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+0x3c2/0x4e0 mm/page-writeback.c:2670
 mark_buffer_dirty+0x148/0x250 fs/buffer.c:1200
 __block_commit_write fs/buffer.c:2175 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2251
 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+0x267/0x410 mm/filemap.c:3941
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x297/0xe10
 call_write_iter include/linux/fs.h:2087 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x760/0x8d0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 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_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88810624e470 of 8 bytes by task 48 on cpu 0:
 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:1961
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2211
 mpage_prepare_extent_to_map+0x321/0xb70 fs/ext4/inode.c:2392
 ext4_do_writepages+0x6ea/0x2100 fs/ext4/inode.c:2632
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 __writeback_single_inode+0x91/0x860 fs/fs-writeback.c:1625
 writeback_sb_inodes+0x514/0xad0 fs/fs-writeback.c:1916
 __writeback_inodes_wb+0x9a/0x1a0 fs/fs-writeback.c:1987
 wb_writeback+0x264/0x6e0 fs/fs-writeback.c:2094
 wb_check_start_all fs/fs-writeback.c:2220 [inline]
 wb_do_writeback fs/fs-writeback.c:2246 [inline]
 wb_workfn+0x4ea/0x8d0 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:243

value changed: 0x0000000040000000 -> 0x00000001c0000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 48 Comm: kworker/u4:3 Not tainted 6.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: writeback wb_workfn (flush-8:0)
==================================================================
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device