oprofile: fix CPU unplug panic in ppro_stop()

If oprofile statically compiled in kernel, a cpu unplug triggers
a panic in ppro_stop(), because a NULL pointer is dereferenced.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>

diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index 716d26f0e5d47b74ae43abb862d7d296c17ef609..e9f80c744cf3409d72f77dd9044ec1dd90534609 100644 (file)
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -156,6 +156,8 @@ static void ppro_start(struct op_msrs const * const msrs)
        unsigned int low, high;
        int i;
 
+       if (!reset_value)
+               return;
        for (i = 0; i < num_counters; ++i) {
                if (reset_value[i]) {
                        CTRL_READ(low, high, msrs, i);
@@ -171,6 +173,8 @@ static void ppro_stop(struct op_msrs const * const msrs)
        unsigned int low, high;
        int i;
 
+       if (!reset_value)
+               return;
        for (i = 0; i < num_counters; ++i) {
                if (!reset_value[i])
                        continue;