This is a note to let you know that I've just added the patch titled
cpu/cacheinfo: Fix teardown path
to the 4.2-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:
cpu-cacheinfo-fix-teardown-path.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2110d70c5e58326a10e93cfefdc0b3686e2ada12 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@xxxxxxx>
Date: Sat, 8 Aug 2015 10:46:02 +0200
Subject: cpu/cacheinfo: Fix teardown path
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From: Borislav Petkov <bp@xxxxxxx>
commit 2110d70c5e58326a10e93cfefdc0b3686e2ada12 upstream.
Philip Müller reported a hang when booting 32-bit 4.1 kernel on an AMD
box. A fragment of the splat was enough to pinpoint the issue:
task: f58e0000 ti: f58e8000 task.ti: f58e800
EIP: 0060:[<c135a903>] EFLAGS: 00010206 CPU: 0
EIP is at free_cache_attributes+0x83/0xd0
EAX: 00000001 EBX: f589d46c ECX: 00000090 EDX: 360c2000
ESI: 00000000 EDI: c1724a80 EBP: f58e9ec0 ESP: f58e9ea0
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 000000ac CR3: 01731000 CR4: 000006d0
cache_shared_cpu_map_setup() did check sibling CPUs cacheinfo descriptor
while the respective teardown path cache_shared_cpu_map_remove() didn't.
Fix that.
>From tglx's version: to be on the safe side, move the cacheinfo
descriptor check to free_cache_attributes(), thus cleaning up the
hotplug path a little and making this even more robust.
Reported-and-tested-by: Philip Müller <philm@xxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Andre Przywara <andre.przywara@xxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: manjaro-dev@xxxxxxxxxxx
Cc: Philip Müller <philm@xxxxxxxxxxx>
Link: https://lkml.kernel.org/r/55B47BB8.6080202@xxxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/cacheinfo.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -148,7 +148,11 @@ static void cache_shared_cpu_map_remove(
if (sibling == cpu) /* skip itself */
continue;
+
sib_cpu_ci = get_cpu_cacheinfo(sibling);
+ if (!sib_cpu_ci->info_list)
+ continue;
+
sib_leaf = sib_cpu_ci->info_list + index;
cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
@@ -159,6 +163,9 @@ static void cache_shared_cpu_map_remove(
static void free_cache_attributes(unsigned int cpu)
{
+ if (!per_cpu_cacheinfo(cpu))
+ return;
+
cache_shared_cpu_map_remove(cpu);
kfree(per_cpu_cacheinfo(cpu));
@@ -514,8 +521,7 @@ static int cacheinfo_cpu_callback(struct
break;
case CPU_DEAD:
cache_remove_dev(cpu);
- if (per_cpu_cacheinfo(cpu))
- free_cache_attributes(cpu);
+ free_cache_attributes(cpu);
break;
}
return notifier_from_errno(rc);
Patches currently in stable-queue which might be from bp@xxxxxxx are
queue-4.2/x86-efi-fix-boot-crash-by-mapping-efi-memmap-entries-bottom-up-at-runtime-instead-of-top-down.patch
queue-4.2/perf-header-fixup-reading-of-header_nrcpus-feature.patch
queue-4.2/kvm-x86-trap-amd-msrs-for-the-tseg-base-and-mask.patch
queue-4.2/perf-probe-use-existing-routine-to-look-for-a-kernel-module-by-dso-short_name.patch
queue-4.2/cpu-cacheinfo-fix-teardown-path.patch
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