Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755236AbYJZO7s (ORCPT ); Sun, 26 Oct 2008 10:59:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753068AbYJZO7k (ORCPT ); Sun, 26 Oct 2008 10:59:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:35746 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753002AbYJZO7j (ORCPT ); Sun, 26 Oct 2008 10:59:39 -0400 From: Bernhard Walle To: kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Bernhard Walle , Wim Van Sebroeck , Thomas Mingarelli , Vivek Goyal Subject: [PATCH] [WATCHDOG] Fix kdump when using hpwdt Date: Sun, 26 Oct 2008 15:59:37 +0100 Message-Id: <1225033177-5311-1-git-send-email-bwalle@suse.de> X-Mailer: git-send-email 1.6.0.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2625 Lines: 68 When the "hpwdt" module is loaded (even if the /dev/watchdog device is not opened), then kdump does not work. The panic kernel either does not start at all or crash in various places. The problem is that hpwdt_pretimeout is registered with register_die_notifier() with the highest possible priority. Because it returns NOTIFY_STOP, the crash_nmi_callback which is also registered with register_die_notifier() is never executed. This causes the shutdown of other CPUs to fail. Reverting the order is no option: The crash_nmi_callback executes HLT and so never returns normally. Because of that, it must be executed as last notifier, which currently is done. So, that patch returns NOTIFY_OK in case allow_kdump is set as module parameter in the hpwdt module. Also, it changes the default of allow_kdump to 1. Kdump is quite common and should be working as default. Signed-off-by: Bernhard Walle Cc: Wim Van Sebroeck Cc: Thomas Mingarelli Cc: Vivek Goyal --- drivers/watchdog/hpwdt.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c index a3765e0..65e7102 100644 --- a/drivers/watchdog/hpwdt.c +++ b/drivers/watchdog/hpwdt.c @@ -116,7 +116,7 @@ static unsigned int reload; /* the computed soft_margin */ static int nowayout = WATCHDOG_NOWAYOUT; static char expect_release; static unsigned long hpwdt_is_open; -static unsigned int allow_kdump; +static unsigned int allow_kdump = 1; static void __iomem *pci_mem_addr; /* the PCI-memory address */ static unsigned long __iomem *hpwdt_timer_reg; @@ -482,7 +482,11 @@ static int hpwdt_pretimeout(struct notifier_block *nb, unsigned long ulReason, "Management Log for details.\n"); } - return NOTIFY_STOP; + /* + * for kdump, we must return NOTIFY_OK here to execute the + * crash_nmi_callback afterwards, see arch/x86/kernel/crash.c + */ + return allow_kdump ? NOTIFY_OK : NOTIFY_STOP; } /* @@ -759,7 +763,7 @@ MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); module_param(soft_margin, int, 0); MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds"); -module_param(allow_kdump, int, 0); +module_param(allow_kdump, int, 1); MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs"); module_param(nowayout, int, 0); -- 1.6.0.2 -- 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/