Commit-ID: 3d98217b6726e0c342ac6363346bd9751fd61ec9
Gitweb: http://git.kernel.org/tip/3d98217b6726e0c342ac6363346bd9751fd61ec9
Author: Rui Wang <rui.y.w...@intel.com>
AuthorDate: Wed, 8 Jun 2016 14:59:52 +0800
Committer: Ingo Molnar <mi...@kernel.org>
CommitDate: Fri, 10 Jun 2016 13:55:03 +0200
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.w...@intel.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: tony.l...@intel.com
Cc: linux-...@vger.kernel.org
Cc: r...@rjwysocki.net
Cc: linux-a...@vger.kernel.org
Cc: bhelg...@google.com
Link:
http://lkml.kernel.org/r/1465369193-4816-3-git-send-email-rui.y.w...@intel.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
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;
