From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.windriver.com (mail.windriver.com [147.11.1.11]) by yocto-www.yoctoproject.org (Postfix) with ESMTP id 73E6EE01239 for ; Thu, 25 Aug 2011 01:12:07 -0700 (PDT) Received: from ALA-HCA.corp.ad.wrs.com (ala-hca [147.11.189.40]) by mail.windriver.com (8.14.3/8.14.3) with ESMTP id p7P8C62t004712 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Thu, 25 Aug 2011 01:12:06 -0700 (PDT) Received: from localhost.localdomain (128.224.162.211) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server id 14.1.255.0; Thu, 25 Aug 2011 01:12:06 -0700 From: Liming Wang To: Date: Thu, 25 Aug 2011 15:55:35 +0800 Message-ID: <1314258935-32230-2-git-send-email-liming.wang@windriver.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1314258935-32230-1-git-send-email-liming.wang@windriver.com> References: <1314258935-32230-1-git-send-email-liming.wang@windriver.com> MIME-Version: 1.0 Cc: yocto@yoctoproject.org, dvhart@linux.intel.com Subject: [PATCH 1/1] mips/rt: convert cascade interrupt to no threaded X-BeenThere: yocto@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Discussion of all things Yocto List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Aug 2011 08:12:07 -0000 Content-Type: text/plain preempt_rt kernel forces all irq interrupts to be threaded except some special interrupts. This cascade interrupt belongs to the exceptions. Because irq2 is initialized more early than "kthreadd" task, which converts irq interrupt to threaded. If this irq is threaded, kernel calls "try_to_wake_up" function to wake up "kthreadd" task, but at that moment, "kthreadd" task hasn't been initialized well, so try_to_wake_up wakes up a NULL task. Signed-off-by: Liming Wang --- arch/mips/kernel/i8259.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c index 5c74eb7..fb338db 100644 --- a/arch/mips/kernel/i8259.c +++ b/arch/mips/kernel/i8259.c @@ -295,6 +295,7 @@ static void init_8259A(int auto_eoi) static struct irqaction irq2 = { .handler = no_action, .name = "cascade", + .flags = IRQF_NO_THREAD, }; static struct resource pic1_io_resource = { -- 1.7.0.4