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 dev…

Overview

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>

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.