This is a note to let you know that I've just added the patch titled
x86/ioapic: Fix incorrect pointers in ioapic_setup_resources()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-ioapic-fix-incorrect-pointers-in-ioapic_setup_resources.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9d98bcec731756b8688b59ec998707924d716d7b Mon Sep 17 00:00:00 2001
From: Rui Wang <rui.y.wang@xxxxxxxxx>
Date: Wed, 8 Jun 2016 14:59:52 +0800
Subject: x86/ioapic: Fix incorrect pointers in ioapic_setup_resources()
From: Rui Wang <rui.y.wang@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: tony.luck@xxxxxxxxx
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: rjw@xxxxxxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: bhelgaas@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1465369193-4816-3-git-send-email-rui.y.wang@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/apic/io_apic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2592,8 +2592,8 @@ static struct resource * __init ioapic_s
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;
Patches currently in stable-queue which might be from rui.y.wang@xxxxxxxxx are
queue-4.4/x86-ioapic-fix-incorrect-pointers-in-ioapic_setup_resources.patch