Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932234AbbBIDcp (ORCPT ); Sun, 8 Feb 2015 22:32:45 -0500 Received: from mgwkm03.jp.fujitsu.com ([202.219.69.170]:49276 "EHLO mgwkm03.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759277AbbBIDco (ORCPT ); Sun, 8 Feb 2015 22:32:44 -0500 X-Greylist: delayed 622 seconds by postgrey-1.27 at vger.kernel.org; Sun, 08 Feb 2015 22:32:43 EST X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Date: Mon, 09 Feb 2015 12:22:04 +0900 (JST) Message-Id: <20150209.122204.284539162.d.hatayama@jp.fujitsu.com> To: bhe@redhat.com Cc: ebiederm@xmission.com, vgoyal@redhat.com, masami.hiramatsu.pt@hitachi.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path From: HATAYAMA Daisuke In-Reply-To: <20150209024030.GA1847@dhcp-16-105.nay.redhat.com> References: <20150205.175943.381586636.d.hatayama@jp.fujitsu.com> <20150209024030.GA1847@dhcp-16-105.nay.redhat.com> X-Mailer: Mew version 6.5 on Emacs 24.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii 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: 2655 Lines: 79 Hello, From: Baoquan He Subject: Re: [PATCH] kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path Date: Mon, 9 Feb 2015 10:40:30 +0800 > On 02/05/15 at 05:59pm, HATAYAMA Daisuke wrote: >> The commit f06e5153f4ae2e2f3b0300f0e260e40cb7fefd45 introduced >> "crash_kexec_post_notifiers" kernel boot option, which toggles >> wheather panic() calls crash_kexec() before or after panic_notifiers >> and dump kmsg. >> >> 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(). >> >> Signed-off-by: HATAYAMA Daisuke >> --- >> include/linux/kernel.h | 3 +++ >> kernel/kexec.c | 2 ++ >> kernel/panic.c | 2 +- >> 3 files changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/kernel.h b/include/linux/kernel.h >> index 64ce58b..f47379f 100644 >> --- a/include/linux/kernel.h >> +++ b/include/linux/kernel.h >> @@ -426,6 +426,9 @@ 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 9a8a01a..0ecf252 100644 >> --- a/kernel/kexec.c >> +++ b/kernel/kexec.c >> @@ -84,6 +84,8 @@ struct resource crashk_low_res = { >> >> int kexec_should_crash(struct task_struct *p) >> { >> + if (crash_kexec_post_notifiers) >> + return 0; >> if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) >> return 1; > > What if these two conditions !p->pid || is_global_init(p) are satisfied? > Seems the behavious is changed. > Please further follow do_exit() path. For each condition, there are the corresponding panic() calls. In summary: oops_end 1) panic() for in_interrupt() 2) panic() for panic_on_oops do_exit 3) panic() for !p->pid (idle task) exit_notify forget_original_parent find_child_reaper 4) panic() for p->pid == 1 (init task) -- Thanks. HATAYAMA, Daisuke -- 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/