CVE-2026-23136: libceph: reset sparse-read state in osd_fault()

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

libceph: reset sparse-read state in osdfault()

When a fault occurs, the connection is abandoned, reestablished, and any pending operations are retried. The OSD client tracks the progress of a sparse-read reply using a separate state machine, largely independent of the messenger's state.

If a connection is lost mid-payload or the sparse-read state machine returns an error, the sparse-read state is not reset. The OSD client will then interpret the beginning of a new reply as the continuation of the old one. If this makes the sparse-read machinery enter a failure state, it may never recover, producing loops like:

libceph: [0] got 0 extents libceph: data len 142248331 != extent len 0 libceph: osd0 (1)...:6801 socket error on read libceph: data len 142248331 != extent len 0 libceph: osd0 (1)...:6801 socket error on read

Therefore, reset the sparse-read state in osdfault(), ensuring retries start from a clean state.