From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756751AbbGGJ6x (ORCPT ); Tue, 7 Jul 2015 05:58:53 -0400 Received: from terminus.zytor.com ([198.137.202.10]:59367 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755502AbbGGJ6n (ORCPT ); Tue, 7 Jul 2015 05:58:43 -0400 Date: Tue, 7 Jul 2015 02:58:14 -0700 From: tip-bot for Thomas Gleixner Message-ID: Cc: bp@suse.de, linux-kernel@vger.kernel.org, yanmin_zhang@linux.intel.com, peterz@infradead.org, mingo@kernel.org, jroedel@suse.de, jin.xiao@intel.com, tglx@linutronix.de, hpa@zytor.com Reply-To: yanmin_zhang@linux.intel.com, bp@suse.de, linux-kernel@vger.kernel.org, jroedel@suse.de, jin.xiao@intel.com, mingo@kernel.org, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de In-Reply-To: <20150705171102.331320612@linutronix.de> References: <20150705171102.331320612@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/irq: Retrieve irq data after locking irq_desc Git-Commit-ID: 09cf92b784fae6109450c5d64f9908066d605249 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 09cf92b784fae6109450c5d64f9908066d605249 Gitweb: http://git.kernel.org/tip/09cf92b784fae6109450c5d64f9908066d605249 Author: Thomas Gleixner AuthorDate: Sun, 5 Jul 2015 17:12:35 +0000 Committer: Thomas Gleixner CommitDate: Tue, 7 Jul 2015 11:54:04 +0200 x86/irq: Retrieve irq data after locking irq_desc irq_data is protected by irq_desc->lock, so retrieving the irq chip from irq_data outside the lock is racy vs. an concurrent update. Move it into the lock held region. While at it add a comment why the vector walk does not require vector_lock. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: xiao jin Cc: Joerg Roedel Cc: Borislav Petkov Cc: Yanmin Zhang Link: http://lkml.kernel.org/r/20150705171102.331320612@linutronix.de --- arch/x86/kernel/irq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 85ca76e..c7dfe1b 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -497,6 +497,11 @@ void fixup_irqs(void) */ mdelay(1); + /* + * We can walk the vector array of this cpu without holding + * vector_lock because the cpu is already marked !online, so + * nothing else will touch it. + */ for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { unsigned int irr; @@ -508,9 +513,9 @@ void fixup_irqs(void) irq = __this_cpu_read(vector_irq[vector]); desc = irq_to_desc(irq); + raw_spin_lock(&desc->lock); data = irq_desc_get_irq_data(desc); chip = irq_data_get_irq_chip(data); - raw_spin_lock(&desc->lock); if (chip->irq_retrigger) { chip->irq_retrigger(data); __this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);