From d26637e3a4b2b175f73d70b838e171ee80fe9886 Mon Sep 17 00:00:00 2001
From: rrobgill <35944068+rrobgill@users.noreply.github.com>
Date: Fri, 4 May 2018 07:21:48 +1000
Subject: [PATCH] cpuid and msr module check

This adds a check before loading the cpuid and msr modules under linux, ensuring they are not unloaded in exit_cleanup() if they were initially present.
---
 spectre-meltdown-checker.sh | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 5bc94f7..f6f1119 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -732,8 +732,12 @@ mount_debugfs()
 load_msr()
 {
 	if [ "$os" = Linux ]; then
-		modprobe msr 2>/dev/null && insmod_msr=1
-		_debug "attempted to load module msr, insmod_msr=$insmod_msr"
+		if ! grep -e msr /proc/modules 2>/dev/null; then
+			modprobe msr 2>/dev/null && insmod_msr=1
+			_debug "attempted to load module msr, insmod_msr=$insmod_cpuid"
+		else
+			_debug "msr module already loaded"
+		fi	
 	else
 		if ! kldstat -q -m cpuctl; then
 			kldload cpuctl 2>/dev/null && kldload_cpuctl=1
@@ -747,8 +751,12 @@ load_msr()
 load_cpuid()
 {
 	if [ "$os" = Linux ]; then
-		modprobe cpuid 2>/dev/null && insmod_cpuid=1
-		_debug "attempted to load module cpuid, insmod_cpuid=$insmod_cpuid"
+		if ! grep -e cpuid /proc/modules 2>/dev/null; then
+			modprobe cpuid 2>/dev/null && insmod_cpuid=1
+			_debug "attempted to load module cpuid, insmod_cpuid=$insmod_cpuid"
+		else
+			_debug "cpuid module already loaded"
+		fi	
 	else
 		if ! kldstat -q -m cpuctl; then
 			kldload cpuctl 2>/dev/null && kldload_cpuctl=1