[PATCH] sysfs: Initialised pci bus legacy_mem field before use

[PATCH] sysfs: Initialised pci bus legacy_mem field before use

[Mel Gorman]

PPC64 is failing to boot the latest mmotm due to an uninitialised pointer in
pci_create_legacy_files(). The surprise is that machines boot at all and it
would appear to affect current mainline as well.  This patch fixes the problem.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
 drivers/pci/pci-sysfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index de29645..9976685 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -655,8 +655,8 @@ void pci_create_legacy_files(struct pci_bus *b)
 		goto legacy_io_err;
 
 	/* Allocated above after the legacy_io struct */
-	sysfs_bin_attr_init(b->legacy_mem);
 	b->legacy_mem = b->legacy_io + 1;
+	sysfs_bin_attr_init(b->legacy_mem);
 	b->legacy_mem->attr.name = "legacy_mem";
 	b->legacy_mem->size = 1024*1024;
 	b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;

Re: [PATCH] sysfs: Initialised pci bus legacy_mem field before use

[Mel Gorman]

On Wed, Mar 10, 2010 at 10:48:34PM +0000, Mel Gorman wrote:
> PPC64 is failing to boot the latest mmotm due to an uninitialised pointer in
> pci_create_legacy_files(). The surprise is that machines boot at all and it
> would appear to affect current mainline as well.  This patch fixes the problem.
> 

I forgot to point out that triggering this problem depends on
CONFIG_DEBUG_LOCK_ALLOC which is why it probably slipped through
testing.

> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> ---
>  drivers/pci/pci-sysfs.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index de29645..9976685 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -655,8 +655,8 @@ void pci_create_legacy_files(struct pci_bus *b)
>  		goto legacy_io_err;
>  
>  	/* Allocated above after the legacy_io struct */
> -	sysfs_bin_attr_init(b->legacy_mem);
>  	b->legacy_mem = b->legacy_io + 1;
> +	sysfs_bin_attr_init(b->legacy_mem);
>  	b->legacy_mem->attr.name = "legacy_mem";
>  	b->legacy_mem->size = 1024*1024;
>  	b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab