[PATCH] percpu: Fix rollback in pcpu_embed_first_chunk()

[PATCH] percpu: Fix rollback in pcpu_embed_first_chunk()

[Michael Holzheu]

From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Subject: percpu: Fix rollback in pcpu_embed_first_chunk()

The "out_free_areas" rollback in pcpu_embed_first_chunk calls the
free_fn() function for all elements in area[]. This is not correct
because not all elements have been allocated.

To fix this we call free_fn() only for allocated elements.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
diff --git a/mm/percpu.c b/mm/percpu.c
index f47af91..5a7f631 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1692,9 +1692,9 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
 	goto out_free;
 
 out_free_areas:
-	for (group = 0; group < ai->nr_groups; group++)
-		free_fn(areas[group],
-			ai->groups[group].nr_units * ai->unit_size);
+	for (;group > 0; group--)
+		free_fn(areas[group - 1],
+			ai->groups[group - 1].nr_units * ai->unit_size);
 out_free:
 	pcpu_free_alloc_info(ai);
 	if (areas)

Re: [PATCH] percpu: Fix rollback in pcpu_embed_first_chunk()

[Tejun Heo]

Hello,

On Wed, May 09, 2012 at 02:39:48PM +0200, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> Subject: percpu: Fix rollback in pcpu_embed_first_chunk()
> 
> The "out_free_areas" rollback in pcpu_embed_first_chunk calls the
> free_fn() function for all elements in area[]. This is not correct
> because not all elements have been allocated.
> 
> To fix this we call free_fn() only for allocated elements.

There's already a pending fix which fixes this and another more
serious problem, which I forgot to push.  I'll push it out today.

  http://article.gmane.org/gmane.linux.kernel/1288808

Thanks.

-- 
tejun