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 socksendmsg() releases all the pages in the underlying biovec array, but the reality is that it doesn't. svcxprtrelease() 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.