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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EEC7C43387 for ; Wed, 16 Jan 2019 12:54:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 368D820675 for ; Wed, 16 Jan 2019 12:54:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392900AbfAPMyc (ORCPT ); Wed, 16 Jan 2019 07:54:32 -0500 Received: from bastet.se.axis.com ([195.60.68.11]:42418 "EHLO bastet.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733128AbfAPMyc (ORCPT ); Wed, 16 Jan 2019 07:54:32 -0500 Received: from localhost (localhost [127.0.0.1]) by bastet.se.axis.com (Postfix) with ESMTP id D268A18525; Wed, 16 Jan 2019 13:54:29 +0100 (CET) X-Axis-User: NO X-Axis-NonUser: YES X-Virus-Scanned: Debian amavisd-new at bastet.se.axis.com Received: from bastet.se.axis.com ([IPv6:::ffff:127.0.0.1]) by localhost (bastet.se.axis.com [::ffff:127.0.0.1]) (amavisd-new, port 10024) with LMTP id noIeBu7GFu-U; Wed, 16 Jan 2019 13:54:29 +0100 (CET) Received: from boulder03.se.axis.com (boulder03.se.axis.com [10.0.8.17]) by bastet.se.axis.com (Postfix) with ESMTPS id 1FA9A1853A; Wed, 16 Jan 2019 13:54:29 +0100 (CET) Received: from boulder03.se.axis.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0BF361E08E; Wed, 16 Jan 2019 13:54:29 +0100 (CET) Received: from boulder03.se.axis.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 000751E086; Wed, 16 Jan 2019 13:54:28 +0100 (CET) Received: from seth.se.axis.com (unknown [10.0.2.172]) by boulder03.se.axis.com (Postfix) with ESMTP; Wed, 16 Jan 2019 13:54:28 +0100 (CET) Received: from lnxartpec.se.axis.com (lnxartpec.se.axis.com [10.88.4.9]) by seth.se.axis.com (Postfix) with ESMTP id E837D11D1; Wed, 16 Jan 2019 13:54:28 +0100 (CET) Received: by lnxartpec.se.axis.com (Postfix, from userid 10564) id E4DA7801F0; Wed, 16 Jan 2019 13:54:28 +0100 (CET) From: Vincent Whitchurch To: akpm@linux-foundation.org Cc: mcgrof@kernel.org, keescook@chromium.org, linux-kernel@vger.kernel.org, Vincent Whitchurch Subject: [PATCH] sysctl: Add panic-fatal-signals Date: Wed, 16 Jan 2019 13:54:22 +0100 Message-Id: <20190116125422.19643-1-vincent.whitchurch@axis.com> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a sysctl which asks the kernel to panic when any userspace process receives a fatal signal which would trigger a core dump. This has proven to be quite useful when debugging problems seen during testing of embedded systems: When combined with kernel core dumps (saved due to the panic), it allows easier debugging of crashes which have their origin in system-wide problems such as buggy drivers or other kernel or hardware-related issues. The crashing process's core dump can be extracted from the kernel core dump using tools such as the crash utility's gcore extension. Signed-off-by: Vincent Whitchurch --- include/linux/signal.h | 1 + kernel/signal.c | 5 ++++- kernel/sysctl.c | 7 +++++++ 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/linux/signal.h b/include/linux/signal.h index cc7e2c1cd444..109efd1432e9 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -10,6 +10,7 @@ struct task_struct; /* for sysctl */ extern int print_fatal_signals; +extern int panic_fatal_signals; static inline void copy_siginfo(kernel_siginfo_t *to, const kernel_siginfo_t *from) diff --git a/kernel/signal.c b/kernel/signal.c index e1d7ad8e6ab1..83c6877b0182 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -59,6 +59,7 @@ static struct kmem_cache *sigqueue_cachep; int print_fatal_signals __read_mostly; +int panic_fatal_signals __read_mostly; static void __user *sig_handler(struct task_struct *t, int sig) { @@ -2497,8 +2498,10 @@ bool get_signal(struct ksignal *ksig) current->flags |= PF_SIGNALED; if (sig_kernel_coredump(signr)) { - if (print_fatal_signals) + if (print_fatal_signals || panic_fatal_signals) print_fatal_signal(ksig->info.si_signo); + if (panic_fatal_signals) + panic("Fatal signal and panic_fatal_signals=1"); proc_coredump_connector(current); /* * If it was able to dump core, this kills all diff --git a/kernel/sysctl.c b/kernel/sysctl.c index ba4d9e85feb8..ad1ac6ec2004 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -557,6 +557,13 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "panic-fatal-signals", + .data = &panic_fatal_signals, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #ifdef CONFIG_SPARC { .procname = "reboot-cmd", -- 2.20.0