[PATCH][2.4.23-pre4] page_alloc uninitialised variable bug

[Mikael Pettersson]

mm/page_alloc in 2.4.23-pre4 triggers this warning:

page_alloc.c: In function `balance_classzone':
page_alloc.c:259: warning: `__freed' might be used uninitialized in this function

There is a case where balance_classzone() returns NULL and an
uninitialised value in *freed, and the caller, __alloc_pages(),
also uses the uninitialised value.

Changing balance_classzone() to not do "*freed = __freed;" in
this case is inadequate since __alloc_pages() will still look
at the bogus value. Someone needs to initialise the damn thing;
the patch below makes balance_classzone() do it.

/Mikael

--- linux-2.4.23-pre4/mm/page_alloc.c.~1~	2003-09-13 19:11:48.000000000 +0200
+++ linux-2.4.23-pre4/mm/page_alloc.c	2003-09-13 20:58:56.000000000 +0200
@@ -256,7 +256,7 @@
 static struct page * balance_classzone(zone_t * classzone, unsigned int gfp_mask, unsigned int order, int * freed)
 {
 	struct page * page = NULL;
-	int __freed;
+	int __freed = 0;
 
 	if (!(gfp_mask & __GFP_WAIT))
 		goto out;
-
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