From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756120Ab2IIXaY (ORCPT ); Sun, 9 Sep 2012 19:30:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51271 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756025Ab2IIXQa (ORCPT ); Sun, 9 Sep 2012 19:16:30 -0400 Message-Id: <20120909224159.746258188@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 09 Sep 2012 23:42:56 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "J. Bruce Fields" Subject: [ 66/95] svcrpc: fix BUG() in svc_tcp_clear_pages In-Reply-To: <20120909224150.641491654@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "J. Bruce Fields" commit be1e44441a560c43c136a562d49a1c9623c91197 upstream. Examination of svc_tcp_clear_pages shows that it assumes sk_tcplen is consistent with sk_pages[] (in particular, sk_pages[n] can't be NULL if sk_tcplen would lead us to expect n pages of data). svc_tcp_restore_pages zeroes out sk_pages[] while leaving sk_tcplen. This is OK, since both functions are serialized by XPT_BUSY. However, that means the inconsistency must be repaired before dropping XPT_BUSY. Therefore we should be ensuring that svc_tcp_save_pages repairs the problem before exiting svc_tcp_recv_record on error. Symptoms were a BUG() in svc_tcp_clear_pages. Signed-off-by: J. Bruce Fields Signed-off-by: Ben Hutchings --- net/sunrpc/svcsock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 18bc130..998aa8c 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1129,9 +1129,9 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp) if (len >= 0) svsk->sk_tcplen += len; if (len != want) { + svc_tcp_save_pages(svsk, rqstp); if (len < 0 && len != -EAGAIN) goto err_other; - svc_tcp_save_pages(svsk, rqstp); dprintk("svc: incomplete TCP record (%d of %d)\n", svsk->sk_tcplen, svsk->sk_reclen); goto err_noclose;