From: Chuck Lever Date: Wed, 21 May 2025 20:34:13 +0000 (-0400) Subject: SUNRPC: Prevent hang on NFS mount with xprtsec=[m]tls X-Git-Tag: v6.16-rc1~54^2~8 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0bd2f6b8996d4f1ca4573652454987826730a04a;p=thirdparty%2Fkernel%2Flinux.git SUNRPC: Prevent hang on NFS mount with xprtsec=[m]tls Engineers at Hammerspace noticed that sometimes mounting with "xprtsec=tls" hangs for a minute or so, and then times out, even when the NFS server is reachable and responsive. kTLS shuts off data_ready callbacks if strp->msg_ready is set to mitigate data_ready callbacks when a full TLS record is not yet ready to be read from the socket. Normally msg_ready is clear when the first TLS record arrives on a socket. However, I observed that sometimes tls_setsockopt() sets strp->msg_ready, and that prevents forward progress because tls_data_ready() becomes a no-op. Moreover, Jakub says: "If there's a full record queued at the time when [tlshd] passes the socket back to the kernel, it's up to the reader to read the already queued data out." So SunRPC cannot expect a data_ready call when ingress data is already waiting. Add an explicit poll after SunRPC's upper transport is set up to pick up any data that arrived after the TLS handshake but before transport set-up is complete. Reported-by: Steve Sears Suggested-by: Jakub Kacinski Fixes: 75eb6af7acdf ("SUNRPC: Add a TCP-with-TLS RPC transport class") Tested-by: Mike Snitzer Reviewed-by: Mike Snitzer Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 83cc095846d35..4b10ecf4c2653 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -2740,6 +2740,11 @@ static void xs_tcp_tls_setup_socket(struct work_struct *work) } rpc_shutdown_client(lower_clnt); + /* Check for ingress data that arrived before the socket's + * ->data_ready callback was set up. + */ + xs_poll_check_readable(upper_transport); + out_unlock: current_restore_flags(pflags, PF_MEMALLOC); upper_transport->clnt = NULL;