From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E9614C4332F for ; Wed, 16 Nov 2022 17:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BhhrT3gVU/zBkvJt/92wQsBYCCUwenCodUKPJO/mLjs=; b=BgkGCnQ+925RFV 4b1TUyk0HVjhnGV8gu6j1HJZ0eI2gQ7MLMWpas0jXPnkHFIIpyW8zmqP7Jf0o4JgbS5UOPbM5EsGx 1rdHXDzrfYYkh4Sjv6Uoim4J0pEluDjnC3j34UFuwIjHZrxAVvFLQumhXt1eIQa2PVJMWj67fxHLj JQ9k0z7QbBtpggleTtfnR3cgrTXBbtdcutv99ie9id1XYgGd5kFMrdLTXnbZ9Ya+Wvn/KWwfdf3IJ t5gBaeO46HAuo6R7FhrPimP6fPwLwbJr9WHZbRUhFaH1xlXj6D2ya+KINGZPGTAroEDTzdWmscgUU ahCLwqdYpJ96wJLQFYIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovMFc-006RFy-Gk; Wed, 16 Nov 2022 17:31:04 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovLAr-005oO9-IX for linux-um@lists.infradead.org; Wed, 16 Nov 2022 16:22:07 +0000 From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1668615720; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eUV7NYFJOYRPWEVh0G/EU6zT1t7HGJ6qLPZoOxwFJX0=; b=i6rR4UWrVsi6o7VcT0dSMzT5OauKeph8Ma1KOTE1b3BM6zKYwJAEGVd6iEJRPcFdOzFCsV HFHmgCNxA9Fub/V2HRwn5xTn33moUGNvgJO1eRSW7ZjzDCd6FDzinZgDymoEquukHZHHq8 s0CfN3++aC4Wd7OuFwJFvCQsDYHtBi7rsrcCbu9lZoG91wvkVze/0dhNIfwRkt0O7vFlHa rE7O6ZmuYj60l/uRvg4R+LV7hz+mhxPJqdVMQJcBtOHc7Hs81xukaMun6CQZh40u/UZ7RM NeBEbscz4y231v4m1OKF/5nSrs2B2K8EMQ5CSNYZsDingtF4zCMr28jZldooGg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1668615720; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eUV7NYFJOYRPWEVh0G/EU6zT1t7HGJ6qLPZoOxwFJX0=; b=DKb9EMCX8Wi5FM8m4Bsdn/mxAv1cbCLE/1Q/F6hUtEvssXkb+GtLbarPzOkGGdX5WYOnik tlusV+pfZJZlBrAA== To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org Subject: [PATCH printk v5 07/40] um: kmsg_dump: only dump when no output console available Date: Wed, 16 Nov 2022 17:27:19 +0106 Message-Id: <20221116162152.193147-8-john.ogness@linutronix.de> In-Reply-To: <20221116162152.193147-1-john.ogness@linutronix.de> References: <20221116162152.193147-1-john.ogness@linutronix.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221116_082205_792471_2051F7F5 X-CRM114-Status: GOOD ( 13.53 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org The initial intention of the UML kmsg_dumper is to dump the kernel buffers to stdout if there is no console available to perform the regular crash output. However, if ttynull was registered as a console, no crash output was seen. Commit e23fe90dec28 ("um: kmsg_dumper: always dump when not tty console") tried to fix this by performing the kmsg_dump unless the stdio console was behind /dev/console or enabled. But this allowed kmsg dumping to occur even if other non-stdio consoles will output the crash output. Also, a console being the driver behind /dev/console has nothing to do with a crash scenario. Restore the initial intention by dumping the kernel buffers to stdout only if a non-ttynull console is registered and enabled. Also add detailed comments so that it is clear why these rules are applied. Signed-off-by: John Ogness Reviewed-by: Petr Mladek --- arch/um/kernel/kmsg_dump.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c index 0224fcb36e22..40abf1e9ccb1 100644 --- a/arch/um/kernel/kmsg_dump.c +++ b/arch/um/kernel/kmsg_dump.c @@ -17,13 +17,22 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, unsigned long flags; size_t len = 0; - /* only dump kmsg when no console is available */ + /* + * If no consoles are available to output crash information, dump + * the kmsg buffer to stdout. + */ + if (!console_trylock()) return; for_each_console(con) { - if(strcmp(con->name, "tty") == 0 && - (con->flags & (CON_ENABLED | CON_CONSDEV)) != 0) { + /* + * The ttynull console and disabled consoles are ignored + * since they cannot output. All other consoles are + * expected to output the crash information. + */ + if (strcmp(con->name, "ttynull") != 0 && + (con->flags & CON_ENABLED)) { break; } } -- 2.30.2 _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um