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 <[EMAIL PROTECTED]>

--- 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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to