FAT-fs (loop4): utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!
FAT-fs (loop4): Invalid FSINFO signature: 0x41615252, 0x80417272 (sector = 1)
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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff888106a90fe0 of 8 bytes by interrupt 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 lib/xarray.c:922 [inline]
 __xa_clear_mark+0xf5/0x1e0 lib/xarray.c:2097
 __folio_end_writeback+0x177/0x470 mm/page-writeback.c:3024
 folio_end_writeback+0x71/0x3d0 mm/filemap.c:1660
 mpage_write_end_io+0x274/0x390 fs/mpage.c:65
 bio_endio+0x374/0x410 block/bio.c:1645
 blk_update_request+0x336/0x730 block/blk-mq.c:987
 blk_mq_end_request+0x26/0x50 block/blk-mq.c:1149
 lo_complete_rq+0x98/0x140 drivers/block/loop.c:304
 blk_complete_reqs block/blk-mq.c:1224 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1229
 handle_softirqs+0xba/0x290 kernel/softirq.c:579
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:968
 smpboot_thread_fn+0x32b/0x530 kernel/smpboot.c:164
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888106a90fe0 of 8 bytes by task 13847 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x218/0x620 lib/xarray.c:1510
 find_get_entry+0x5d/0x380 mm/filemap.c:2038
 filemap_get_folios_tag+0x13b/0x210 mm/filemap.c:2306
 __filemap_fdatawait_range mm/filemap.c:530 [inline]
 file_write_and_wait_range+0x1ea/0x2c0 mm/filemap.c:798
 __generic_file_fsync+0x46/0x140 fs/libfs.c:1526
 fat_file_fsync+0x49/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x10a/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3031 [inline]
 generic_file_write_iter+0x1b8/0x2f0 mm/filemap.c:4259
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x4a0/0x8e0 fs/read_write.c:686
 ksys_write+0xda/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x2cdd/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000007 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13847 Comm: syz.4.2557 Not tainted 6.16.0-rc3-syzkaller-00190-g67a993863163 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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