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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 2C207C433EF for ; Thu, 28 Apr 2022 01:40:25 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Kpdbq669Fz3dyf for ; Thu, 28 Apr 2022 11:40:23 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=nwXMrZIm; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=igalia.com (client-ip=178.60.130.6; helo=fanzine2.igalia.com; envelope-from=gpiccoli@igalia.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=nwXMrZIm; dkim-atps=neutral Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4KpYwL1ftcz2yWn for ; Thu, 28 Apr 2022 08:54:26 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=gwBR7P38mmxeEI4wWnwfuOo3Vx6Wo8buxtIoJ+/ueVE=; b=nwXMrZImrRof6aT4nflSriZWm8 nV+2kfTnZMr3qMfu/pdKx8zdoFC6dPSZfgjMR8nrCqKQx0a9STr9zXRmf603LSCMYxoe/0rzj8WAX X04mzyflhbAneN3N3eqd1bEuJEgnFV2TubG1LTS2zdwee0DTxDCCfkp/jZLLefrxcRie9zAR6UkMF CbBI0mU22IJBGJ0ER3H7bHP1OaQk7bRcIVlpHROO0rfL6uLx6VUv9a0aPf+94uNbhp5w7FYgnWnfd FC3cJ2sUp+UEhn1teUMFvXk88fY0u++AP/ytEp5+rJzALI+oR2Quq3NLCvwKLKxi/cwHyaoyY3uHg LhfKC/tQ==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqY1-0002Ha-Aa; Thu, 28 Apr 2022 00:54:15 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Subject: [PATCH 17/30] tracing: Improve panic/die notifiers Date: Wed, 27 Apr 2022 19:49:11 -0300 Message-Id: <20220427224924.592546-18-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Thu, 28 Apr 2022 11:34:03 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-hyperv@vger.kernel.org, halves@canonical.com, gregkh@linuxfoundation.org, peterz@infradead.org, alejandro.j.jimenez@oracle.com, linux-remoteproc@vger.kernel.org, feng.tang@intel.com, linux-mips@vger.kernel.org, hidehiro.kawai.ez@hitachi.com, sparclinux@vger.kernel.org, will@kernel.org, tglx@linutronix.de, linux-leds@vger.kernel.org, linux-s390@vger.kernel.org, mikelley@microsoft.com, john.ogness@linutronix.de, corbet@lwn.net, paulmck@kernel.org, fabiomirmar@gmail.com, x86@kernel.org, mingo@redhat.com, bcm-kernel-feedback-list@broadcom.com, xen-devel@lists.xenproject.org, dyoung@redhat.com, vgoyal@redhat.com, linux-xtensa@linux-xtensa.org, dave.hansen@linux.intel.com, keescook@chromium.org, arnd@arndb.de, linux-pm@vger.kernel.org, coresight@lists.linaro.org, linux-um@lists.infradead.org, rostedt@goodmis.org, rcu@vger.kernel.org, bp@alien8.de, luto@kernel.org, linux-tegra@vger.kernel.org, openipmi-developer@lists.sourceforge.net, andriy.shevchenko@linux.intel.com, senozhatsky@chromium.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, jgross@suse.com, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, kernel@gpiccoli.net, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, gpiccoli@igalia.com, d.hatayama@jp.fujitsu.com, mhiramat@kernel.org, kernel-dev@igalia.com, linux-alpha@vger.kernel.org, vkuznets@redhat.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Currently the tracing dump_on_oops feature is implemented through separate notifiers, one for die/oops and the other for panic. With the addition of panic notifier "id", this patch makes use of such "id" to unify both functions. It also comments the function and changes the priority of the notifier blocks, in order they run early compared to other notifiers, to prevent useless trace data (like the callback names for the other notifiers). Finally, we also removed an unnecessary header inclusion. Signed-off-by: Guilherme G. Piccoli --- kernel/trace/trace.c | 57 +++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 25 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f4de111fa18f..c1d8a3622ccc 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -19,7 +19,6 @@ #include #include #include -#include #include #include #include @@ -9767,38 +9766,46 @@ static __init int tracer_init_tracefs(void) fs_initcall(tracer_init_tracefs); -static int trace_panic_handler(struct notifier_block *this, - unsigned long event, void *unused) +/* + * The idea is to execute the following die/panic callback early, in order + * to avoid showing irrelevant information in the trace (like other panic + * notifier functions); we are the 2nd to run, after hung_task/rcu_stall + * warnings get disabled (to prevent potential log flooding). + */ +static int trace_die_panic_handler(struct notifier_block *self, + unsigned long ev, void *unused) { - if (ftrace_dump_on_oops) + int do_dump; + + if (!ftrace_dump_on_oops) + return NOTIFY_DONE; + + switch (ev) { + case DIE_OOPS: + do_dump = 1; + break; + case PANIC_NOTIFIER: + do_dump = 1; + break; + default: + do_dump = 0; + break; + } + + if (do_dump) ftrace_dump(ftrace_dump_on_oops); - return NOTIFY_OK; + + return NOTIFY_DONE; } static struct notifier_block trace_panic_notifier = { - .notifier_call = trace_panic_handler, - .next = NULL, - .priority = 150 /* priority: INT_MAX >= x >= 0 */ + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, }; -static int trace_die_handler(struct notifier_block *self, - unsigned long val, - void *data) -{ - switch (val) { - case DIE_OOPS: - if (ftrace_dump_on_oops) - ftrace_dump(ftrace_dump_on_oops); - break; - default: - break; - } - return NOTIFY_OK; -} - static struct notifier_block trace_die_notifier = { - .notifier_call = trace_die_handler, - .priority = 200 + .notifier_call = trace_die_panic_handler, + .priority = INT_MAX - 1, }; /* -- 2.36.0