[PATCH] Reduce stack usage in module.c

[Yum Rayan <yum.rayan@gmail.com>]

Attempt to reduce stack usage in module.c (linux-2.6.12-rc1-mm3). 
Specifically from checkstack.pl

Before patch
------------------
who_is_doing_it: 512 
obsolete_params: 160

After patch
----------------
who_is_doing_it: none
obsolete_params: 12

Also while at it, fix following in who_is_doing_it(...)
- use only as much memory is needed
- do not write past array index for the boundary case

Patch is against linux-2.6.12-rc1-mm3

Thanks,
Rayan

Signed-off-by: Yum Rayan <yum.rayan@gmail.com>

--- kernel/module.c.orig	2005-03-28 22:32:35.000000000 -0800
+++ kernel/module.c	2005-03-28 22:49:26.000000000 -0800
@@ -769,15 +769,25 @@
 	struct kernel_param *kp;
 	unsigned int i;
 	int ret;
+	char *sym_name = NULL;
+	unsigned int sym_name_len = 0;
 
 	kp = kmalloc(sizeof(kp[0]) * num, GFP_KERNEL);
 	if (!kp)
 		return -ENOMEM;
 
-	for (i = 0; i < num; i++) {
-		char sym_name[128 + sizeof(MODULE_SYMBOL_PREFIX)];
+	if (num) {
+		sym_name_len = 128 + sizeof (MODULE_SYMBOL_PREFIX);
+		sym_name = kmalloc(sym_name_len, GFP_KERNEL);
+		if (!sym_name) {
+			ret = -ENOMEM;
+			goto free_kp;
+		}
+	}
 
-		snprintf(sym_name, sizeof(sym_name), "%s%s",
+	for (i = 0; i < num; i++) {
+		
+		snprintf(sym_name, sym_name_len, "%s%s",
 			 MODULE_SYMBOL_PREFIX, obsparm[i].name);
 
 		kp[i].name = obsparm[i].name;
@@ -791,13 +801,15 @@
 			printk("%s: falsely claims to have parameter %s\n",
 			       name, obsparm[i].name);
 			ret = -EINVAL;
-			goto out;
+			goto free_sym;
 		}
 		kp[i].arg = &obsparm[i];
 	}
 
 	ret = parse_args(name, args, kp, num, NULL);
- out:
+ free_sym:
+	kfree(sym_name);
+ free_kp:
 	kfree(kp);
 	return ret;
 }
@@ -1399,12 +1411,16 @@
 static void who_is_doing_it(void)
 {
 	/* Print out all the args. */
-	char args[512];
+	char *args;
 	unsigned long i, len = current->mm->arg_end - current->mm->arg_start;
 
 	if (len > 512)
 		len = 512;
 
+	args = kmalloc(len + 1, GFP_KERNEL);
+	if (!args)
+		return;
+
 	len -= copy_from_user(args, (void *)current->mm->arg_start, len);
 
 	for (i = 0; i < len; i++) {
@@ -1413,6 +1429,7 @@
 	}
 	args[i] = 0;
 	printk("ARGS: %s\n", args);
+	kfree(args);
 }
 
 /* Allocate and load the module: note that size of section 0 is always
-
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