Red Hat: CVE-2024-35882: kernel: SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP

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

SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP

Jan Schunk reports that his small NFS servers suffer from memory
exhaustion after just a few days. A bisect shows that commit
e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single
sock_sendmsg() call") is the first bad commit.

That commit assumed that sock_sendmsg() releases all the pages in
the underlying bio_vec array, but the reality is that it doesn't.
svc_xprt_release() releases the rqst's response pages, but the
record marker page fragment isn't one of those, so it is never
released.

This is a narrow fix that can be applied to stable kernels. A
more extensive fix is in the works.