Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757279Ab2BHCev (ORCPT ); Tue, 7 Feb 2012 21:34:51 -0500 Received: from am1ehsobe001.messaging.microsoft.com ([213.199.154.204]:3489 "EHLO AM1EHSOBE005.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756607Ab2BHCeu (ORCPT ); Tue, 7 Feb 2012 21:34:50 -0500 X-SpamScore: 0 X-BigFish: VPS0(zzzz1202hzz8275bhz2fh668h839h93fh) X-Forefront-Antispam-Report: CIP:160.33.98.74;KIP:(null);UIP:(null);IPV:NLI;H:mail7.fw-bc.sony.com;RD:mail7.fw-bc.sony.com;EFVD:NLI Message-ID: <4F31DF34.8000205@am.sony.com> Date: Tue, 7 Feb 2012 18:34:28 -0800 From: Tim Bird User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.12) Gecko/20100907 Fedora/3.0.7-1.fc12 Thunderbird/3.0.7 MIME-Version: 1.0 To: Greg KH , linux-embedded , linux kernel , Brian Swetland , Dima Zavin , Andrew Morton Subject: [PATCH 5/5] logger: clarify non-update of w_off in do_write_log_from_user References: <4F31DC31.6040303@am.sony.com> In-Reply-To: <4F31DC31.6040303@am.sony.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-OriginatorOrg: am.sony.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1173 Lines: 33 Add comment to explain when w_off is not updated in case of failed second fragment copy to buffer. Signed-off-by: Tim Bird --- drivers/staging/android/logger.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index 8d9d4f1..115d8ed 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -330,6 +330,12 @@ static ssize_t do_write_log_from_user(struct logger_log *log, if (count != len) if (copy_from_user(log->buffer, buf + len, count - len)) + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ return -EFAULT; log->w_off = logger_offset(log, log->w_off + count); -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/