[PATCH] stop NULL pointer dereference in __alloc_pages

Martin J. Bligh (Martin.Bligh@us.ibm.com)
Thu, 18 Apr 2002 15:38:14 -0700


This trivial patch will apply to both 2.4.19-pre7 and 2.5.8 with just line
offsets. It stops us from following a NULL pointer in classzone in the case
where there is a pgdat without a fully populated zone list (ie a node with
no ZONE_NORMAL on an ia32 NUMA machine). Without this patch, ia32
NUMA machines won't even boot - we dereference the classzone ptr
a few lines further down (or try to ;-) ).

Please apply ...

Thanks,

Martin.

--- linux-2.4.18-memalloc/mm/page_alloc.c.old Fri Mar 8 18:21:41 2002
+++ linux-2.4.18-memalloc/mm/page_alloc.c Fri Mar 8 18:23:27 2002
@@ -317,6 +317,8 @@

zone = zonelist->zones;
classzone = *zone;
+ if (classzone == NULL)
+ return NULL;
min = 1UL << order;
for (;;) {
zone_t *z = *(zone++);

-
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