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-rw-r--r--kernel/params.c52
1 files changed, 50 insertions, 2 deletions
diff --git a/kernel/params.c b/kernel/params.c
index 458a09b886c4..ef60db14fae0 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -31,6 +31,45 @@
#define DEBUGP(fmt, a...)
#endif
+/* This just allows us to keep track of which parameters are kmalloced. */
+struct kmalloced_param {
+ struct list_head list;
+ char val[];
+};
+static DEFINE_MUTEX(param_lock);
+static LIST_HEAD(kmalloced_params);
+
+static void *kmalloc_parameter(unsigned int size)
+{
+ struct kmalloced_param *p;
+
+ p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
+ if (!p)
+ return NULL;
+
+ mutex_lock(&param_lock);
+ list_add(&p->list, &kmalloced_params);
+ mutex_unlock(&param_lock);
+
+ return p->val;
+}
+
+/* Does nothing if parameter wasn't kmalloced above. */
+static void maybe_kfree_parameter(void *param)
+{
+ struct kmalloced_param *p;
+
+ mutex_lock(&param_lock);
+ list_for_each_entry(p, &kmalloced_params, list) {
+ if (p->val == param) {
+ list_del(&p->list);
+ kfree(p);
+ break;
+ }
+ }
+ mutex_unlock(&param_lock);
+}
+
static inline char dash2underscore(char c)
{
if (c == '-')
@@ -219,12 +258,15 @@ int param_set_charp(const char *val, const struct kernel_param *kp)
return -ENOSPC;
}
- /* This is a hack. We can't need to strdup in early boot, and we
+ maybe_kfree_parameter(*(char **)kp->arg);
+
+ /* This is a hack. We can't kmalloc in early boot, and we
* don't need to; this mangled commandline is preserved. */
if (slab_is_available()) {
- *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
+ *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
if (!*(char **)kp->arg)
return -ENOMEM;
+ strcpy(*(char **)kp->arg, val);
} else
*(const char **)kp->arg = val;
@@ -238,9 +280,15 @@ int param_get_charp(char *buffer, const struct kernel_param *kp)
}
EXPORT_SYMBOL(param_get_charp);
+static void param_free_charp(void *arg)
+{
+ maybe_kfree_parameter(*((char **)arg));
+}
+
struct kernel_param_ops param_ops_charp = {
.set = param_set_charp,
.get = param_get_charp,
+ .free = param_free_charp,
};
EXPORT_SYMBOL(param_ops_charp);