From patchwork Fri Jul 18 21:28:03 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alex Elder X-Patchwork-Id: 33910 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id 0FEC4208CF for ; Fri, 18 Jul 2014 21:28:29 +0000 (UTC) Received: by mail-pa0-f70.google.com with SMTP id lf10sf31558811pab.9 for ; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:delivered-to:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:sender:precedence:list-id :x-original-sender:x-original-authentication-results:mailing-list :list-post:list-help:list-archive:list-unsubscribe:content-type :content-transfer-encoding; bh=ihzbU0eeTnVrZmLj4sSRFQywF26nb6KGcZ3ppvyHpO8=; b=QBLSuLZfBD4kNzQubjHZmJCmBWjoc1U9W/tAXDIxsEIBf8KgyGKHO/+bh5Xk/CxIsN dm3WytYgzUp93Agbn5c9UXZdbJeMm5jiIyhbLRDMbbbW1mjBAVB4fmUVen7IiSd/ByLm 24X83L4S0vinb6V82vw6il3HeQcW47u4lQJ9McuqM2Qu81N67E1d+W7452zFgedDXBe4 yXyD8yL/8OQ/NHBozqepJ/pGFjpKYty96VBos36VZltEq5dcjFhIUOefTfA4hWqjaCGX zHBVIqABPX2kb1fXteprMRoIpKGfmIRCGGqDv9PMmziU335Lz9LSb6huNCzN+o/xcmiw IJnw== X-Gm-Message-State: ALoCoQl7OXSEJhh8QpE3mHi5P/T1BcDb1orFFigf/KAr2kxbaDUoUeyNfTaC1cwU6+j16iqhSoXH X-Received: by 10.66.163.41 with SMTP id yf9mr3722465pab.36.1405718909379; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) X-BeenThere: patchwork-forward@linaro.org Received: by 10.140.42.117 with SMTP id b108ls1151566qga.19.gmail; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) X-Received: by 10.220.187.134 with SMTP id cw6mr9570175vcb.3.1405718909224; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) Received: from mail-vc0-f177.google.com (mail-vc0-f177.google.com [209.85.220.177]) by mx.google.com with ESMTPS id x3si6947585vep.58.2014.07.18.14.28.29 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 18 Jul 2014 14:28:29 -0700 (PDT) Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.220.177 as permitted sender) client-ip=209.85.220.177; Received: by mail-vc0-f177.google.com with SMTP id hy4so8497437vcb.36 for ; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) X-Received: by 10.53.5.230 with SMTP id cp6mr1338201vdd.25.1405718909074; Fri, 18 Jul 2014 14:28:29 -0700 (PDT) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patch@linaro.org Received: by 10.221.37.5 with SMTP id tc5csp42331vcb; Fri, 18 Jul 2014 14:28:28 -0700 (PDT) X-Received: by 10.70.22.98 with SMTP id c2mr8233348pdf.3.1405718907179; Fri, 18 Jul 2014 14:28:27 -0700 (PDT) Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id h13si3620856pdl.42.2014.07.18.14.28.26; Fri, 18 Jul 2014 14:28:26 -0700 (PDT) Received-SPF: none (google.com: linux-kernel-owner@vger.kernel.org does not designate permitted sender hosts) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946136AbaGRV2R (ORCPT + 23 others); Fri, 18 Jul 2014 17:28:17 -0400 Received: from mail-ie0-f173.google.com ([209.85.223.173]:48355 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946105AbaGRV2O (ORCPT ); Fri, 18 Jul 2014 17:28:14 -0400 Received: by mail-ie0-f173.google.com with SMTP id tr6so5067222ieb.32 for ; Fri, 18 Jul 2014 14:28:14 -0700 (PDT) X-Received: by 10.43.28.82 with SMTP id rt18mr11264180icb.22.1405718894134; Fri, 18 Jul 2014 14:28:14 -0700 (PDT) Received: from localhost.localdomain (c-24-245-18-91.hsd1.mn.comcast.net. [24.245.18.91]) by mx.google.com with ESMTPSA id vk3sm9535840igb.17.2014.07.18.14.28.13 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 18 Jul 2014 14:28:13 -0700 (PDT) From: Alex Elder To: akpm@linux-foundation.org Cc: kay@vrfy.org, pmladek@suse.cz, bp@suse.de, john.stultz@linaro.org, jack@suse.cz, linux-kernel@vger.kernel.org Subject: [PATCH v4 5/7] printk: honor LOG_PREFIX in msg_print_text() Date: Fri, 18 Jul 2014 16:28:03 -0500 Message-Id: <1405718885-11227-6-git-send-email-elder@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1405718885-11227-1-git-send-email-elder@linaro.org> References: <1405718885-11227-1-git-send-email-elder@linaro.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: elder@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.220.177 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , This patch fixes a problem similar to what was addressed in the previous patch. All paths that read and format log records (for consoles, and for reading via syslog and /dev/kmsg) go through msg_print_text(). That function starts with some logic to determine whether the given log record when formatted should begin with a "prefix" string, and whether it should end with a newline. That logic has a bug. The LOG_PREFIX flag in a log record indicates that when it's formatted, a log record should include a prefix. This is used to force a record to begin a new line--even if its preceding log record contained LOG_CONT (indicating its content should be combined with the next record). Like the previous patch, the problem occurs when these flags are all set: prev & LOG_CONT msg->flags & LOG_PREFIX msg->flags & LOG_CONT In that case, "prefix" should be true but it is not. The fix involves checking LOG_PREFIX when a message has its LOG_CONT flag set, and in that case allowing "prefix" to become false only if LOG_PREFIX is not set. I.e., the logic for "prefix" would become: if (prev & LOG_CONT && !(msg->flags & LOG_PREFIX)) prefix = false; if (msg->flags & LOG_CONT) if (prev & LOG_CONT && !(msg->flags & LOG_PREFIX)) prefix = false; However, note that this makes the (msg->flags & LOG_CONT) block redunant--it's handled by the test just above it. The result becomes quite a bit simpler than before. The following table concisely defines the problem: prev | msg | msg || CONT |PREFIX| CONT ||prefix ------+------+------++------ clear| clear| clear|| true clear| clear| set || true clear| set | clear|| true clear| set | set || true set | clear| clear|| false set | clear| set || false set | set | clear|| true set | set | set || false <-- should be true Signed-off-by: Alex Elder Reviewed-by: Petr Mládek --- kernel/printk/printk.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f8ab63c..e9f0632 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1006,11 +1006,8 @@ static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) prefix = false; - if (msg->flags & LOG_CONT) { - if (prev & LOG_CONT) - prefix = false; + if (msg->flags & LOG_CONT) newline = false; - } do { const char *next = memchr(text, '\n', text_size);