Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934146AbbEOLMX (ORCPT ); Fri, 15 May 2015 07:12:23 -0400 Received: from mgwym01.jp.fujitsu.com ([211.128.242.40]:32772 "EHLO mgwym01.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754417AbbEOLMH (ORCPT ); Fri, 15 May 2015 07:12:07 -0400 X-Greylist: delayed 619 seconds by postgrey-1.27 at vger.kernel.org; Fri, 15 May 2015 07:12:05 EDT Subject: [PATCH v3 2/2] kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path From: HATAYAMA Daisuke To: akpm@linux-foundation.org, ebiederm@xmission.com, vgoyal@redhat.com, mingo@kernel.org Cc: masami.hiramatsu.pt@hitachi.com, hidehiro.kawai.ez@hitachi.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bhe@redhat.com Date: Fri, 15 May 2015 20:01:49 +0900 Message-ID: <20150515110149.8431.38054.stgit@localhost6.localdomain6> In-Reply-To: <20150515105953.8431.65220.stgit@localhost6.localdomain6> References: <20150515105953.8431.65220.stgit@localhost6.localdomain6> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2758 Lines: 80 The commit f06e5153f4ae2e2f3b0300f0e260e40cb7fefd45 introduced "crash_kexec_post_notifiers" kernel boot option, which toggles wheather panic() calls crash_kexec() before panic_notifiers and dump kmsg or after. The problem is that the commit overlooks panic_on_oops kernel boot option. If it is enabled, crash_kexec() is called directly without going through panic() in oops path. To fix this issue, this patch adds a check to "crash_kexec_post_notifiers" in the condition of kexec_should_crash(). Also, put a comment in kexec_should_crash() to explain not obvious things on this patch. Signed-off-by: HATAYAMA Daisuke Acked-by: Baoquan He Tested-by: Hidehiro Kawai Reviewed-by: Masami Hiramatsu --- include/linux/kernel.h | 3 +++ kernel/kexec.c | 11 +++++++++++ kernel/panic.c | 2 +- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3a5b48e..bd5331c 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -438,6 +438,9 @@ extern int panic_on_unrecovered_nmi; extern int panic_on_io_nmi; extern int panic_on_warn; extern int sysctl_panic_on_stackoverflow; + +extern bool crash_kexec_post_notifiers; + /* * Only to be used by arch init code. If the user over-wrote the default * CONFIG_PANIC_TIMEOUT, honor it. diff --git a/kernel/kexec.c b/kernel/kexec.c index 7a36fdc..a785c10 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -84,6 +84,17 @@ struct resource crashk_low_res = { int kexec_should_crash(struct task_struct *p) { + /* + * If crash_kexec_post_notifiers is enabled, don't run + * crash_kexec() here yet, which must be run after panic + * notifiers in panic(). + */ + if (crash_kexec_post_notifiers) + return 0; + /* + * There are 4 panic() calls in do_exit() path, each of which + * corresponds to each of these 4 conditions. + */ if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) return 1; return 0; diff --git a/kernel/panic.c b/kernel/panic.c index 774614f..04e91ff 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -32,7 +32,7 @@ static unsigned long tainted_mask; static int pause_on_oops; static int pause_on_oops_flag; static DEFINE_SPINLOCK(pause_on_oops_lock); -static bool crash_kexec_post_notifiers; +bool crash_kexec_post_notifiers; int panic_on_warn __read_mostly; int panic_timeout = CONFIG_PANIC_TIMEOUT; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/