syzbot

loop0: detected capacity change from 0 to 128
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BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff8881065a0238 of 8 bytes by task 3684 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_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
 __mpage_writepage+0xbed/0xe10 fs/mpage.c:619
 write_cache_pages+0x62/0x100 mm/page-writeback.c:2644
 mpage_writepages+0x72/0xf0 fs/mpage.c:666
 fat_writepages+0x24/0x30 fs/fat/inode.c:199
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2687
 filemap_fdatawrite_wbc mm/filemap.c:388 [inline]
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0x146/0x360 mm/filemap.c:693
 filemap_invalidate_pages+0xa5/0x1a0 mm/filemap.c:2805
 kiocb_invalidate_pages mm/filemap.c:2824 [inline]
 generic_file_direct_write+0x9d/0x250 mm/filemap.c:4029
 __generic_file_write_iter+0xae/0x120 mm/filemap.c:4205
 generic_file_write_iter+0x8f/0x310 mm/filemap.c:4245
 aio_write+0x2f7/0x420 fs/aio.c:1633
 io_submit_one+0xb0c/0x1230 fs/aio.c:2052
 __do_sys_io_submit fs/aio.c:2111 [inline]
 __se_sys_io_submit+0xf5/0x280 fs/aio.c:2081
 __x64_sys_io_submit+0x43/0x50 fs/aio.c:2081
 x64_sys_call+0x2c20/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:210
 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 0xffff8881065a0238 of 8 bytes by task 3677 on cpu 0:
 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:2027
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2294
 writeback_get_folio mm/page-writeback.c:2493 [inline]
 writeback_iter+0x4b0/0x830 mm/page-writeback.c:2594
 write_cache_pages+0x4b/0x100 mm/page-writeback.c:2643
 mpage_writepages+0x72/0xf0 fs/mpage.c:666
 fat_writepages+0x24/0x30 fs/fat/inode.c:199
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2687
 filemap_fdatawrite_wbc mm/filemap.c:388 [inline]
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0x168/0x2f0 mm/filemap.c:796
 __generic_file_fsync+0x46/0x140 fs/libfs.c:1525
 fat_file_fsync+0x46/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2970 [inline]
 generic_file_write_iter+0x1c3/0x310 mm/filemap.c:4249
 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

value changed: 0xfffffffffffffffc -> 0xfffffffffffffff0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3677 Comm: syz.0.104 Not tainted 6.14.0-rc7-syzkaller-00196-g88d324e69ea9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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