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BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff8881062e3478 of 8 bytes by task 3554 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_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark+0x90/0x180 lib/xarray.c:921
 __folio_start_writeback+0x2f1/0x430 mm/page-writeback.c:3145
 ext4_bio_write_folio+0x591/0x9d0 fs/ext4/page-io.c:556
 mpage_submit_folio fs/ext4/inode.c:1932 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2178 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2310 [inline]
 ext4_do_writepages+0x1221/0x2130 fs/ext4/inode.c:2735
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2824
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2687
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 file_write_and_wait_range+0x168/0x2f0 mm/filemap.c:797
 generic_buffers_fsync_noflush+0x46/0x120 fs/buffer.c:600
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ff/0x6c0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2970 [inline]
 ext4_buffered_write_iter+0x358/0x3c0 fs/ext4/file.c:305
 ext4_file_write_iter+0x383/0xf20
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77b/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881062e3478 of 8 bytes by task 3557 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1733 [inline]
 xas_find_marked+0x217/0x650 lib/xarray.c:1377
 find_get_entry+0x54/0x390 mm/filemap.c:2017
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2284
 mpage_prepare_extent_to_map+0x329/0xb80 fs/ext4/inode.c:2448
 ext4_do_writepages+0x6ea/0x2130 fs/ext4/inode.c:2688
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2824
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2687
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 filemap_write_and_wait_range+0x146/0x360 mm/filemap.c:694
 ext4_punch_hole+0xbf/0x7e0 fs/ext4/inode.c:3964
 ext4_fallocate+0x1f1/0x1170 fs/ext4/extents.c:4772
 vfs_fallocate+0x368/0x3b0 fs/open.c:338
 madvise_remove mm/madvise.c:1034 [inline]
 madvise_vma_behavior mm/madvise.c:1269 [inline]
 madvise_walk_vmas mm/madvise.c:1511 [inline]
 do_madvise+0x14da/0x2ad0 mm/madvise.c:1698
 __do_sys_madvise mm/madvise.c:1714 [inline]
 __se_sys_madvise mm/madvise.c:1712 [inline]
 __x64_sys_madvise+0x61/0x70 mm/madvise.c:1712
 x64_sys_call+0x23ab/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:29
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x001ffffffffffffe -> 0x001ffffffffffff8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3557 Comm: syz.4.44 Not tainted 6.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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syz.4.44 (3557) used greatest stack depth: 9656 bytes left