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

write to 0xffff888119822f04 of 4 bytes by task 12612 on cpu 0:
 xa_mark_set lib/xarray.c:71 [inline]
 xas_set_mark lib/xarray.c:899 [inline]
 __xa_set_mark+0x192/0x1c0 lib/xarray.c:1943
 __folio_mark_dirty+0x3b5/0x4e0 mm/page-writeback.c:2798
 mark_buffer_dirty+0x134/0x230 fs/buffer.c:1196
 __block_commit_write fs/buffer.c:2189 [inline]
 block_write_end+0x123/0x210 fs/buffer.c:2265
 ext4_write_end+0x148/0x770 fs/ext4/inode.c:1306
 generic_perform_write+0x31e/0x4b0 mm/filemap.c:4135
 ext4_buffered_write_iter+0x1ed/0x3c0 fs/ext4/file.c:299
 ext4_file_write_iter+0x3b2/0xf80 include/linux/fs.h:-1
 iter_file_splice_write+0x5f2/0x980 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x160/0x2c0 fs/splice.c:1158
 splice_direct_to_actor+0x305/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xd9/0x150 fs/splice.c:1227
 do_sendfile+0x40a/0x690 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
 x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888119822f04 of 4 bytes by task 12623 on cpu 1:
 xa_marked include/linux/xarray.h:424 [inline]
 xas_find_marked+0x614/0x660 lib/xarray.c:1350
 find_get_entry+0x54/0x390 mm/filemap.c:2039
 filemap_get_folios_tag+0xa0/0x220 mm/filemap.c:2306
 __filemap_fdatawait_range mm/filemap.c:533 [inline]
 file_write_and_wait_range+0x206/0x2f0 mm/filemap.c:801
 generic_buffers_fsync_noflush+0x46/0x120 fs/buffer.c:600
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1c3/0x6c0 fs/ext4/fsync.c:147
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2976 [inline]
 ext4_buffered_write_iter+0x358/0x3c0 fs/ext4/file.c:305
 ext4_file_write_iter+0x3b2/0xf80 include/linux/fs.h:-1
 iter_file_splice_write+0x5f2/0x980 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x160/0x2c0 fs/splice.c:1158
 splice_direct_to_actor+0x305/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xd9/0x150 fs/splice.c:1227
 do_sendfile+0x40a/0x690 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
 x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x04000021 -> 0x0e000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12623 Comm: syz.9.3065 Not tainted 6.14.0-syzkaller-07486-g15cb9a2b66fc #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================