staging: lustre: libcfs: avoid stomping on module param cpu_pattern

The function cfs_cpt_table_create_pattern() alters the string
passed to it. Currently we are passing in the module parameter
string cpu_pattern which is incorrect. Instead lets duplicate
the module parameter string and pass that to the function
cfs_cpt_table_create_pattern().
Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5050
Reviewed-on: http://review.whamcloud.com/22377Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Olaf Weber <olaf@sgi.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c

@@ -1050,7 +1050,15 @@ cfs_cpu_init(void)
 	ret = -EINVAL;
 
 	if (*cpu_pattern) {
-		cfs_cpt_table = cfs_cpt_table_create_pattern(cpu_pattern);
+		char *cpu_pattern_dup = kstrdup(cpu_pattern, GFP_KERNEL);
+
+		if (!cpu_pattern_dup) {
+			CERROR("Failed to duplicate cpu_pattern\n");
+			goto failed;
+		}
+
+		cfs_cpt_table = cfs_cpt_table_create_pattern(cpu_pattern_dup);
+		kfree(cpu_pattern_dup);
 		if (!cfs_cpt_table) {
 			CERROR("Failed to create cptab from pattern %s\n",
 			       cpu_pattern);