From patchwork Tue Oct 1 19:15:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Druzhinin X-Patchwork-Id: 11169495 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5B25D13BD for ; Tue, 1 Oct 2019 19:17:34 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 351202133F for ; Tue, 1 Oct 2019 19:17:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="C6J4DBXk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 351202133F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iFNcy-0003PP-PG; Tue, 01 Oct 2019 19:16:04 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iFNcy-0003PK-6X for xen-devel@lists.xenproject.org; Tue, 01 Oct 2019 19:16:04 +0000 X-Inumbo-ID: e84c0576-e47f-11e9-9707-12813bfff9fa Received: from esa6.hc3370-68.iphmx.com (unknown [216.71.155.175]) by localhost (Halon) with ESMTPS id e84c0576-e47f-11e9-9707-12813bfff9fa; Tue, 01 Oct 2019 19:16:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1569957362; h=from:to:cc:subject:date:message-id:mime-version; bh=a2IUMnJku1CYcf8X9Skx3RU/jroqUS1+A9CIrrErbAA=; b=C6J4DBXk1x/dok1rzmjSr1PL1IFA7reDu9GZAu39wDJToCsBRDe0xHFh PvOG2tGjQ7osH8VOh8GhgeudVJiT3uvdo+bgKXrcO8Favd4rS1PmLNPEc 6S24oFtk9HqVi1BpeAGAHQeeSqw4pLOYhJDB24CDlWs3/ZhbPkAt1U7CZ k=; Authentication-Results: esa6.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=igor.druzhinin@citrix.com; spf=Pass smtp.mailfrom=igor.druzhinin@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender authenticity information available from domain of igor.druzhinin@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="igor.druzhinin@citrix.com"; x-sender="igor.druzhinin@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa6.hc3370-68.iphmx.com: domain of igor.druzhinin@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="igor.druzhinin@citrix.com"; x-sender="igor.druzhinin@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa6.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="igor.druzhinin@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: h80v/L78EIMC/lKt5lop0JK0yKVhSW4e9PBHDVJ5shQM2BfqZqlVk9ZbCdVwIFrYts/9beNzIX H8Zk3umP9JqZWKs/dYDydsER4SOTt98Lqn0YE+dRDtmaZSfUa8QNPzzksDZ4nOJRj21iYM8guL YOVZKun98ylIL8z+pJUz/r66fFTb/wAPQqQeEBfD81sy+8Wwi3JldVE5hcXqRA9vMroIIAAuZ1 8zfq9yyZi9hXOd/JO/Ms6aG0kQkVV1Rk0w4gJTr+oAvybq5OqrwqROJQa77bcbojgkfS6FX7l0 nlE= X-SBRS: 2.7 X-MesageID: 6625096 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.64,571,1559534400"; d="scan'208";a="6625096" From: Igor Druzhinin To: Date: Tue, 1 Oct 2019 20:15:57 +0100 Message-ID: <1569957357-20803-1-git-send-email-igor.druzhinin@citrix.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Subject: [Xen-devel] [PATCH for-4.13] x86/crash: force unlock console before printing on kexec crash X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: andrew.cooper3@citrix.com, Igor Druzhinin , wl@xen.org, jbeulich@suse.com, roger.pau@citrix.com Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" There is a small window where shootdown NMI might come to a CPU (e.g. in serial interrupt handler) where console lock is taken. In order not to leave following console prints waiting infinitely for shot down CPUs to free the lock - force unlock the console. The race has been frequently observed while crashing nested Xen in an HVM domain. Signed-off-by: Igor Druzhinin --- xen/arch/x86/crash.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/arch/x86/crash.c b/xen/arch/x86/crash.c index 6e1d3d3..a20ec8a 100644 --- a/xen/arch/x86/crash.c +++ b/xen/arch/x86/crash.c @@ -29,6 +29,7 @@ #include #include #include +#include static cpumask_t waiting_to_crash; static unsigned int crashing_cpu; @@ -155,6 +156,7 @@ static void nmi_shootdown_cpus(void) } /* Leave a hint of how well we did trying to shoot down the other cpus */ + console_force_unlock(); if ( cpumask_empty(&waiting_to_crash) ) printk("Shot down all CPUs\n"); else