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authorThomas Renninger <trenn@suse.de>2009-12-14 11:44:15 +0100
committerDave Jones <davej@redhat.com>2010-01-13 10:55:15 -0500
commit557a701c16553b0b691dbb64ef30361115a80f64 (patch)
tree1160ab1c446311f5ca3a483b322cbc9ffcbc83ef /arch
parent292e0041c3b22c5347092152504d814119554b57 (diff)
downloadop-kernel-dev-557a701c16553b0b691dbb64ef30361115a80f64.zip
op-kernel-dev-557a701c16553b0b691dbb64ef30361115a80f64.tar.gz
[CPUFREQ] Fix use after free of struct powernow_k8_data
Easy fix for a regression introduced in 2.6.31. On managed CPUs the cpufreq.c core will call driver->exit(cpu) on the managed cpus and powernow_k8 will free the core's data. Later driver->get(cpu) function might get called trying to read out the current freq of a managed cpu and the NULL pointer check does not work on the freed object -> better set it to NULL. ->get() is unsigned and must return 0 as invalid frequency. Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14391 Signed-off-by: Thomas Renninger <trenn@suse.de> Tested-by: Michal Schmidt <mschmidt@redhat.com> CC: stable@kernel.org Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/cpufreq/powernow-k8.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
index a9df944..2da4fa3 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c
@@ -1356,6 +1356,7 @@ static int __devexit powernowk8_cpu_exit(struct cpufreq_policy *pol)
kfree(data->powernow_table);
kfree(data);
+ per_cpu(powernow_data, pol->cpu) = NULL;
return 0;
}
@@ -1375,7 +1376,7 @@ static unsigned int powernowk8_get(unsigned int cpu)
int err;
if (!data)
- return -EINVAL;
+ return 0;
smp_call_function_single(cpu, query_values_on_cpu, &err, true);
if (err)
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