Re: 2.6.18-rc7-mm1 -- ppc64 crash in slab_node ??

[Christoph Lameter]

On Thu, 21 Sep 2006, Andrew Morton wrote:

> I guess the below will fix it.  But Christoph's machine would have oopsed
> too, if it had called fallback_alloc() this early.  So presumably it did
> not.  But yours does.  I wonder why?

Hmmm... Fallback during boot? Any zones that have no ZONE_NORMAL memory?

The right fix though is to check for a NULL memory policy in slab_node. 
This is the way other mempol functions behave.

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

Index: linux-2.6.18-rc7-mm1/mm/mempolicy.c
===================================================================
--- linux-2.6.18-rc7-mm1.orig/mm/mempolicy.c	2006-09-19 09:27:03.000000000 -0500
+++ linux-2.6.18-rc7-mm1/mm/mempolicy.c	2006-09-21 12:59:09.385528424 -0500
@@ -1136,7 +1136,9 @@ static unsigned interleave_nodes(struct 
  */
 unsigned slab_node(struct mempolicy *policy)
 {
-	switch (policy->policy) {
+	int pol = policy ? policy->policy : MPOL_DEFAULT;
+
+	switch (pol) {
 	case MPOL_INTERLEAVE:
 		return interleave_nodes(policy);
 
-
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