Re: [PATCH] list_add corruption in slab.c

From: Daniel Yeisley
Date: Tue Mar 25 2008 - 17:03:08 EST


On Tue, 2008-03-25 at 20:45 +0200, Pekka Enberg wrote:
> Hi Daniel,
>
> On Tue, Mar 25, 2008 at 6:57 PM, Daniel Yeisley <dan.yeisley@xxxxxxxxxx> wrote:
> > I've been seeing list_add corruption in slab.c on the ES7000 since the
> > 2.6.24.1 kernel. There are several places where the initkmem_list3
> > array is access by [somevalue + node]. This also needs to be done in
> > kmem_cache_init().
> >
> > Signed-off-by: Dan Yeisley <dan.yeisley@xxxxxxxxxx>
> >
> > ---
> > diff -Naur linux-2.6.25-rc5/mm/slab.c linux-2.6.25-rc5-new/mm/slab.c
> > --- linux-2.6.25-rc5/mm/slab.c 2008-03-10 01:22:27.000000000 -0400
> > +++ linux-2.6.25-rc5-new/mm/slab.c 2008-03-20 13:59:24.000000000 -0400
> > @@ -1481,7 +1481,7 @@
> > list_add(&cache_cache.next, &cache_chain);
> > cache_cache.colour_off = cache_line_size();
> > cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
> > - cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE];
> > + cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
>
> Good catch! You'd need to fix up the use of initkmem_list3 farther
> down in kmem_init_cache():
>
> > /* 5) Replace the bootstrap kmem_list3's */
> > {
> > int nid;
> >
> > for_each_online_node(nid) {
> > init_list(&cache_cache, &initkmem_list3[CACHE_CACHE], nid);
>
> Care to send a tested patch that fixes that as well?
>
> Pekka

I actually saw that initkmem_list reference, but didn't change it since
my original patch fixed my list corruption. Anyway, I made the changed
and tested it. The system booted fine.

ïSigned-off-by: Dan Yeisley <dan.yeisley@xxxxxxxxxx>

---
diff -Nuar linux-2.6.25-rc6/mm/slab.c linux-2.6.25-rc6-new/mm/slab.c
--- linux-2.6.25-rc6/mm/slab.c 2008-03-25 15:39:07.000000000 -0400
+++ linux-2.6.25-rc6-new/mm/slab.c 2008-03-25 15:13:01.000000000 -0400
@@ -1481,7 +1481,7 @@
list_add(&cache_cache.next, &cache_chain);
cache_cache.colour_off = cache_line_size();
cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
- cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE];
+ cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];

/*
* struct kmem_cache size depends on nr_node_ids, which
@@ -1602,7 +1602,7 @@
int nid;

for_each_online_node(nid) {
- init_list(&cache_cache, &initkmem_list3[CACHE_CACHE], nid);
+ init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);

init_list(malloc_sizes[INDEX_AC].cs_cachep,
&initkmem_list3[SIZE_AC + nid], nid);

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