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>