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,URIBL_BLOCKED, 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 BD28EC282C8 for ; Mon, 28 Jan 2019 08:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 956AF20880 for ; Mon, 28 Jan 2019 08:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726914AbfA1IuL (ORCPT ); Mon, 28 Jan 2019 03:50:11 -0500 Received: from bastet.se.axis.com ([195.60.68.11]:54270 "EHLO bastet.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726415AbfA1IuL (ORCPT ); Mon, 28 Jan 2019 03:50:11 -0500 Received: from localhost (localhost [127.0.0.1]) by bastet.se.axis.com (Postfix) with ESMTP id 23ABA180C0; Mon, 28 Jan 2019 09:50:09 +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 gby93N2I57df; Mon, 28 Jan 2019 09:50:08 +0100 (CET) Received: from boulder02.se.axis.com (boulder02.se.axis.com [10.0.8.16]) by bastet.se.axis.com (Postfix) with ESMTPS id 261B4183E8; Mon, 28 Jan 2019 09:50:08 +0100 (CET) Received: from boulder02.se.axis.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B40771A069; Mon, 28 Jan 2019 09:50:07 +0100 (CET) Received: from boulder02.se.axis.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A84031A067; Mon, 28 Jan 2019 09:50:07 +0100 (CET) Received: from seth.se.axis.com (unknown [10.0.2.172]) by boulder02.se.axis.com (Postfix) with ESMTP; Mon, 28 Jan 2019 09:50:07 +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 9BDFDF8; Mon, 28 Jan 2019 09:50:07 +0100 (CET) Received: by lnxartpec.se.axis.com (Postfix, from userid 10564) id 9874F80126; Mon, 28 Jan 2019 09:50:07 +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 v2] sysctl: Add panic-fatal-signals Date: Mon, 28 Jan 2019 09:49:59 +0100 Message-Id: <20190128084959.13060-1-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 --- v2: Put the sysctl behind a config option include/linux/signal.h | 1 + init/Kconfig | 14 ++++++++++++++ kernel/signal.c | 5 ++++- kernel/sysctl.c | 9 +++++++++ 4 files changed, 28 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/init/Kconfig b/init/Kconfig index d47cb77a220e..875442f6ab53 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1242,6 +1242,20 @@ config SYSCTL_SYSCALL If unsure say N here. +config SYSCTL_PANIC_FATAL_SIGNALS + bool "panic-fatal-signals sysctl" if EXPERT + depends on PROC_SYSCTL + help + If you say Y here, a kernel.panic-fatal-signals sysctl will be + offered. If this sysctl is turned on, the kernel will panic if any + userspace process receives a fatal signal which would trigger a core + dump. + + When used together with kernel core dumps, this can be useful for + debugging some system-wide problems, primarily on embedded systems. + + If unsure, say N. + config FHANDLE bool "open by fhandle syscalls" if EXPERT select EXPORTFS 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..48023bad5b08 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -557,6 +557,15 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, +#ifdef CONFIG_SYSCTL_PANIC_FATAL_SIGNALS + { + .procname = "panic-fatal-signals", + .data = &panic_fatal_signals, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +#endif #ifdef CONFIG_SPARC { .procname = "reboot-cmd", -- 2.20.0