From: Eric Dumazet <dada1@cosmosbay.com>
Date: Tue, 2 Dec 2008 06:21:21 +0000 (+0100)
Subject: oprofile: fix CPU unplug panic in ppro_stop()
X-Git-Tag: firefly_0821_release~16609^2~1^2~1
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9ea84ad77d635bdb76c9a08f44f21a9af98359ee;p=firefly-linux-kernel-4.4.55.git

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 716d26f0e5d4..e9f80c744cf3 100644
--- 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;