Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753552Ab2HGKnB (ORCPT ); Tue, 7 Aug 2012 06:43:01 -0400 Received: from mga14.intel.com ([143.182.124.37]:26335 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751170Ab2HGKnA (ORCPT ); Tue, 7 Aug 2012 06:43:00 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="177849967" Message-ID: <5020E4F0.5060203@intel.com> Date: Tue, 07 Aug 2012 18:50:40 +0900 From: "Chen, LinX Z" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100922 Thunderbird/3.1.4 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, yanmin_zhang@linux.intel.com Subject: [PATCH] x86/smp: Fix cpuN startup panic Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2169 Lines: 61 From: Lin Chen We hit a panic while doing cpu hotplug test. <0>[ 627.982857] Kernel panic - not syncing: smp_callin: CPU1 started up but did not get a callout! <0>[ 627.982864] <4>[ 627.982876] Pid: 0, comm: kworker/0:1 Tainted: G ... <4>[ 627.982883] Call Trace: <4>[ 627.982903] [] panic+0x66/0x16c <4>[ 627.982918] [] ? default_get_apic_id+0x1c/0x40 <4>[ 627.982931] [] start_secondary+0xda/0x252 During BSP bootup AP, it is possible that BSP be preempted before finishing STARTUP sequence of AP(set cpu_callout_mask) which maybe cause AP busy wait for it. At present, AP will wait for 2 seconds then panic. This patch let AP waits until BSP finish the startup sequence and gives WARNING when BSP is preempted more than 2 seconds. Signed-off-by: Yanmin Zhang Signed-off-by: Lin Chen --- arch/x86/kernel/smpboot.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 7c5a8c3..a9e3379 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -165,19 +165,20 @@ static void __cpuinit smp_callin(void) * Waiting 2s total for startup (udelay is not yet working) */ timeout = jiffies + 2*HZ; - while (time_before(jiffies, timeout)) { + while (1) { /* * Has the boot CPU finished it's STARTUP sequence? */ if (cpumask_test_cpu(cpuid, cpu_callout_mask)) break; cpu_relax(); + if (!time_before(jiffies, timeout)) { + WARN(1, "%s: CPU%d started up but did not get a callout!\n", + __func__, cpuid); + timeout = jiffies + 2*HZ; + } } - if (!time_before(jiffies, timeout)) { - panic("%s: CPU%d started up but did not get a callout!\n", - __func__, cpuid); - } /* * the boot CPU has finished the init stage and is spinning -- 1.7.1 -- 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/