From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rui Wang Subject: [PATCH V2 2/3] x86/ioapic: Fix wrong pointers in ioapic_setup_resources() Date: Wed, 8 Jun 2016 14:59:52 +0800 Message-ID: <1465369193-4816-3-git-send-email-rui.y.wang@intel.com> References: <1465369193-4816-1-git-send-email-rui.y.wang@intel.com> Return-path: In-Reply-To: <1465369193-4816-1-git-send-email-rui.y.wang@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: tglx@linutronix.de, rjw@rjwysocki.net, tony.luck@intel.com, bhelgaas@google.com Cc: linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, rui.y.wang@intel.com List-Id: linux-acpi@vger.kernel.org On a 4-socket brickland, hot-removing one ioapic is fine. Hot-removing the 2nd one causes panic in mp_unregister_ioapic() while calling release_resource(). It is because the iomem_res pointer has already been released when removing the first ioapic. Fix it by assigning the correct pointers to ioapics[i].iomem_res in ioapic_setup_resources(). To explain the use of &res[num] here: res is assigned to ioapic_resources, and later in ioapic_insert_resources() we do struct resource *r = ioapic_resources; for_each_ioapic(i) { insert_resource(&iomem_resource, r); r++; } Here r is treated as an arry of struct resource, and the r++ ensures that each element of the array is inserted separately. Thus we should call release_resouce() on each element at &res[num]. Signed-off-by: Rui Wang --- arch/x86/kernel/apic/io_apic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 84e33ff..446702e 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2588,8 +2588,8 @@ static struct resource * __init ioapic_setup_resources(void) res[num].flags = IORESOURCE_MEM | IORESOURCE_BUSY; snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i); mem += IOAPIC_RESOURCE_NAME_SIZE; + ioapics[i].iomem_res = &res[num]; num++; - ioapics[i].iomem_res = res; } ioapic_resources = res; -- 1.8.3.1