x86/ioapic: Fix incorrect pointers in ioapic_setup_resources()
authorRui Wang <rui.y.wang@intel.com>
Wed, 8 Jun 2016 06:59:52 +0000 (14:59 +0800)
committerIngo Molnar <mingo@kernel.org>
Fri, 10 Jun 2016 12:45:54 +0000 (14:45 +0200)
commit9d98bcec731756b8688b59ec998707924d716d7b
treef532e712dd97ca994dde1ee5563188b6d0c454bb
parentaaee8c3c5cce2d9107310dd9f3026b4f901d441c
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 <rui.y.wang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
arch/x86/kernel/apic/io_apic.c