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| author | Thomas Renninger <trenn@suse.de> | 2009-12-14 11:44:15 +0100 |
|---|---|---|
| committer | Dave Jones <davej@redhat.com> | 2010-01-13 16:55:15 +0100 |
| commit | 557a701c16553b0b691dbb64ef30361115a80f64 (patch) | |
| tree | 1160ab1c446311f5ca3a483b322cbc9ffcbc83ef | |
| parent | [CPUFREQ] fix default value for ondemand governor (diff) | |
| download | linux-557a701c16553b0b691dbb64ef30361115a80f64.tar.xz linux-557a701c16553b0b691dbb64ef30361115a80f64.zip | |
[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>
| -rw-r--r-- | arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 3 |
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 a9df9441a9a2..2da4fa3bf6e9 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) |