1 files changed, 25 insertions, 1 deletions

diff --git a/kernel/params.c b/kernel/params.c
index a1e3025b19a9..de273ec85bd2 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -24,6 +24,9 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 
+/* We abuse the high bits of "perm" to record whether we kmalloc'ed. */
+#define KPARAM_KMALLOCED        0x80000000
+
 #if 0
 #define DEBUGP printk
 #else
@@ -217,7 +220,19 @@ int param_set_charp(const char *val, struct kernel_param *kp)
                 return -ENOSPC;
         }
 
-        *(char **)kp->arg = (char *)val;
+        if (kp->perm & KPARAM_KMALLOCED)
+                kfree(*(char **)kp->arg);
+
+        /* This is a hack.  We can't need to strdup in early boot, and we
+         * don't need to; this mangled commandline is preserved. */
+        if (slab_is_available()) {
+                kp->perm |= KPARAM_KMALLOCED;
+                *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
+                if (!kp->arg)
+                        return -ENOMEM;
+        } else
+                *(const char **)kp->arg = val;
+
         return 0;
 }
 
@@ -571,6 +586,15 @@ void module_param_sysfs_remove(struct module *mod)
 }
 #endif
 
+void destroy_params(const struct kernel_param *params, unsigned num)
+{
+        unsigned int i;
+
+        for (i = 0; i < num; i++)
+                if (params[i].perm & KPARAM_KMALLOCED)
+                        kfree(*(char **)params[i].arg);
+}
+
 static void __init kernel_add_sysfs_param(const char *name,
                                           struct kernel_param *kparam,
                                           unsigned int name_skip)