CVE-2026-97610netfs: Fix uninitialized return value in netfs_unbuffered_write()

Official description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix uninitialized return value in netfs_unbuffered_write() If preparation of the first subrequest fails, netfs_unbuffered_write() exits its loop before ret is initialized. The empty-iterator check can do the same. For synchronous writes, netfs_unbuffered_write_iter_locked() may then return an unrelated error instead of wreq->error. This is reachable through CIFS if cifs_prepare_write() fails to reopen the file or obtain credits. Initialize ret to 0 so the caller returns wreq->error if no data was written, or the number of bytes already written otherwise. Found with Clang's -Wconditional-uninitialized.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/3d038eebdbd400c3bc4b66bd8aa0dff0c2bcce26
• https://git.kernel.org/stable/c/2e38d500471d097cda87d7d374bbc1b13493075d
• https://git.kernel.org/stable/c/f18e8774f4d3137fa0a5fb8ffa83d59a719666d8