From: Rui Wang Date: Wed, 8 Jun 2016 06:59:52 +0000 (+0800) Subject: x86/ioapic: Fix incorrect pointers in ioapic_setup_resources() X-Git-Tag: v4.7-rc3~13^2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=9d98bcec731756b8688b59ec998707924d716d7b;p=linux.git x86/ioapic: Fix incorrect pointers in ioapic_setup_resources() On a 4-socket Brickland system, 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. 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]. Fix it by assigning the correct pointers to ioapics[i].iomem_res in ioapic_setup_resources(). Signed-off-by: Rui Wang Signed-off-by: Thomas Gleixner Cc: tony.luck@intel.com Cc: linux-pci@vger.kernel.org Cc: rjw@rjwysocki.net Cc: linux-acpi@vger.kernel.org Cc: bhelgaas@google.com Link: http://lkml.kernel.org/r/1465369193-4816-3-git-send-email-rui.y.wang@intel.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 84e33ff5a6d5..446702ed99dc 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;