From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Rui Wang <rui.y.wang@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
tony.luck@intel.com, linux-pci@vger.kernel.org,
rjw@rjwysocki.net, linux-acpi@vger.kernel.org,
bhelgaas@google.com, Ingo Molnar <mingo@kernel.org>,
Joerg Roedel <jroedel@suse.de>
Subject: [PATCH 4.4 26/74] x86/ioapic: Fix incorrect pointers in ioapic_setup_resources()
Date: Mon, 29 Jan 2018 13:56:31 +0100 [thread overview]
Message-ID: <20180129123848.802267981@linuxfoundation.org> (raw)
In-Reply-To: <20180129123847.507563674@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rui Wang <rui.y.wang@intel.com>
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>
---
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;
parent reply other threads:[~2018-01-29 12:56 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20180129123847.507563674@linuxfoundation.org>]
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