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.

Reported-by: Jan Schunk <[email protected]>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218671
Fixes: e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single sock_sendmsg() call")
Cc: Alexander Duyck <[email protected]>
Cc: Jakub Kacinski <[email protected]>
Cc: David Howells <[email protected]>
Reviewed-by: David Howells <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

0 files changed, 0 insertions, 0 deletions