Linux EUVD-2026-38931

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

dm cache: fix write hang in passthrough mode

The invalidate_remove() function has incomplete logic for handling write hit bios after cache invalidation. It sets up the remapping for the overwrite_bio but then drops it immediately without submission, causing write operations to hang.

Fix by adding a new invalidate_committed() continuation that submits the remapped writes to the cache origin after metadata commit completes, while using the overwrite_endio hook to ensure proper completion sequencing. This maintains existing coherency. Also improve error handling in invalidate_complete() to preserve the original error status instead of using bio_io_error() unconditionally.