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x86/ioapic: Fix incorrect pointers in ioapic_setup_resources()

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commit 9d98bcec731756b8688b59ec998707924d716d7b upstream.

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>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rui Wang 2016-06-08 14:59:52 +08:00 • committed by Greg Kroah-Hartman
parent bab93a6196
commit 699a6cc7dd
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kernel/apic/io_apic.c
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@ -2592,8 +2592,8 @@ 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;