CVE-2026-93140

In the Linux kernel, the following vulnerability has been resolved:

udf: Mark LVID buffer as uptodate before marking it dirty

When an I/O error occurs while writing the Logical Volume Integrity
Descriptor (LVID) buffer to the block device, the block layer's completion
handler (`end_buffer_write_sync()`) clears the `BH_Uptodate` flag on the
buffer. However, the buffer still contains valid LVID data in memory. If
the filesystem is subsequently remounted read-write or synced,
`udf_open_lvid()` or `udf_sync_fs()` will modify the LVID buffer and call
`mark_buffer_dirty()`. This triggers a spurious
`WARN_ON_ONCE(!buffer_uptodate(bh))` warning in `mark_buffer_dirty()`
because the buffer is not marked uptodate, even though its in-memory
contents are valid and are about to be overwritten.

To prevent this spurious warning, unconditionally set the `BH_Uptodate`
flag before calling `mark_buffer_dirty()` in `udf_open_lvid()` and
`udf_sync_fs()`. This acknowledges that the in-memory buffer is valid and
matches the workaround previously applied to `udf_close_lvid()` in commit
853a0c25baf9 ("udf: Mark LVID buffer as uptodate before marking it dirty").
Extending this workaround ensures consistent behavior across all LVID
updates.

Buffer I/O error on dev loop0, logical block 128, lost sync page write
------------[ cut here ]------------
!buffer_uptodate(bh)
WARNING: fs/buffer.c:1087 at mark_buffer_dirty+0x299/0x410 fs/buffer.c:1087
...
Call Trace:
 <TASK>
 udf_open_lvid+0x369/0x5b0 fs/udf/super.c:2078
 udf_reconfigure+0x336/0x540 fs/udf/super.c:679
 reconfigure_super+0x232/0x8f0 fs/super.c:1080
 vfs_cmd_reconfigure fs/fsopen.c:268 [inline]
 vfs_fsconfig_locked+0x171/0x320 fs/fsopen.c:297
 __do_sys_fsconfig fs/fsopen.c:463 [inline]
 __se_sys_fsconfig+0x6b9/0x810 fs/fsopen.c:350
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 </TASK>