From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id QjNsIPtIGVuPTAAAmS7hNA ; Thu, 07 Jun 2018 15:04:46 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 6AF33608BA; Thu, 7 Jun 2018 15:04:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 3A04B6089E; Thu, 7 Jun 2018 15:04:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 3A04B6089E Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965100AbeFGPEn (ORCPT + 25 others); Thu, 7 Jun 2018 11:04:43 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41585 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936055AbeFGPEQ (ORCPT ); Thu, 7 Jun 2018 11:04:16 -0400 Received: from [148.252.241.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1fQvbm-0005dI-6K; Thu, 07 Jun 2018 15:09:46 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1fQvb3-0002tZ-BB; Thu, 07 Jun 2018 15:09:01 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Tejun Heo" , "Ivan Vecera" , "Al Viro" Date: Thu, 07 Jun 2018 15:05:21 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 145/410] kernfs: fix regression in kernfs_fop_write caused by wrong type In-Reply-To: X-SA-Exim-Connect-IP: 148.252.241.226 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.57-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ivan Vecera commit ba87977a49913129962af8ac35b0e13e0fa4382d upstream. Commit b7ce40cff0b9 ("kernfs: cache atomic_write_len in kernfs_open_file") changes type of local variable 'len' from ssize_t to size_t. This change caused that the *ppos value is updated also when the previous write callback failed. Mentioned snippet: ... len = ops->write(...); <- return value can be negative ... if (len > 0) <- true here in this case *ppos += len; ... Fixes: b7ce40cff0b9 ("kernfs: cache atomic_write_len in kernfs_open_file") Acked-by: Tejun Heo Signed-off-by: Ivan Vecera Signed-off-by: Al Viro Signed-off-by: Ben Hutchings --- fs/kernfs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -267,7 +267,7 @@ static ssize_t kernfs_fop_write(struct f { struct kernfs_open_file *of = kernfs_of(file); const struct kernfs_ops *ops; - size_t len; + ssize_t len; char *buf; if (of->atomic_write_len) {