From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752692Ab2GZPQo (ORCPT ); Thu, 26 Jul 2012 11:16:44 -0400 Received: from terminus.zytor.com ([198.137.202.10]:38170 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752426Ab2GZPQm (ORCPT ); Thu, 26 Jul 2012 11:16:42 -0400 Date: Thu, 26 Jul 2012 08:16:24 -0700 From: tip-bot for Tomoki Sekiyama Message-ID: Cc: linux-kernel@vger.kernel.org, agordeev@redhat.com, hpa@zytor.com, mingo@kernel.org, yinghai@kernel.org, tomoki.sekiyama.qu@hitachi.com, suresh.b.siddha@intel.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, agordeev@redhat.com, linux-kernel@vger.kernel.org, yinghai@kernel.org, suresh.b.siddha@intel.com, tglx@linutronix.de, tomoki.sekiyama.qu@hitachi.com In-Reply-To: <20120726104732.2889.19144.stgit@kvmdev> References: <20120726104732.2889.19144.stgit@kvmdev> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs Git-Commit-ID: 1d44b30f35a9873a65b320dd5300088fa995fd94 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 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Thu, 26 Jul 2012 08:16:30 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1d44b30f35a9873a65b320dd5300088fa995fd94 Gitweb: http://git.kernel.org/tip/1d44b30f35a9873a65b320dd5300088fa995fd94 Author: Tomoki Sekiyama AuthorDate: Thu, 26 Jul 2012 19:47:32 +0900 Committer: Ingo Molnar CommitDate: Thu, 26 Jul 2012 15:01:17 +0200 x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs In the current kernel, percpu variable `vector_irq' is not always cleared when a CPU is offlined. If the CPU that has the disabled irqs in vector_irq is hotplugged again, __setup_vector_irq() hits invalid irq vector and may crash. This bug can be reproduced as following; # echo 0 > /sys/devices/system/cpu/cpu7/online # modprobe -r some_driver_using_interrupts # vector_irq@cpu7 uncleared # echo 1 > /sys/devices/system/cpu/cpu7/online # kernel may crash To fix this problem, this patch clears vector_irq in __fixup_irqs() when the CPU is offlined. This also reverts commit f6175f5bfb4c, which partially fixes this bug by clearing vector in __clear_irq_vector(). But in environments with IOMMU IRQ remapper, it could fail because cfg->domain doesn't contain offlined CPUs. With this patch, the fix in __clear_irq_vector() can be reverted because every vector_irq is already cleared in __fixup_irqs() on offlined CPUs. Signed-off-by: Tomoki Sekiyama Acked-by: Suresh Siddha Cc: yrl.pp-manager.tt@hitachi.com Cc: Yinghai Lu Cc: Alexander Gordeev Link: http://lkml.kernel.org/r/20120726104732.2889.19144.stgit@kvmdev Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/io_apic.c | 4 ++-- arch/x86/kernel/irq.c | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 406eee7..a6c64aa 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1204,7 +1204,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) BUG_ON(!cfg->vector); vector = cfg->vector; - for_each_cpu(cpu, cfg->domain) + for_each_cpu_and(cpu, cfg->domain, cpu_online_mask) per_cpu(vector_irq, cpu)[vector] = -1; cfg->vector = 0; @@ -1212,7 +1212,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) if (likely(!cfg->move_in_progress)) return; - for_each_cpu(cpu, cfg->old_domain) { + for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) { for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { if (per_cpu(vector_irq, cpu)[vector] != irq) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 1f5f1d5..7ad683d 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -328,6 +328,7 @@ void fixup_irqs(void) chip->irq_retrigger(data); raw_spin_unlock(&desc->lock); } + __this_cpu_write(vector_irq[vector], -1); } } #endif