Re: [patch 1/2 -resend] dma-debug: debugfs_create_bool() takes a u32pointer

From: Neil Horman
Date: Wed Jun 27 2012 - 07:10:11 EST


On Wed, Jun 27, 2012 at 12:08:55PM +0300, Dan Carpenter wrote:
> Even though it has "bool" in the name, you have pass a u32 pointer to
> debugfs_create_bool(). Otherwise you get memory corruption in
> write_file_bool(). Fortunately in this case the corruption happens in
> an alignment hole between variables so it doesn't cause any problems.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>

> ---
> This was sent on Fri, 2 Mar 2012.
>
> It's probably my fault the bug is still there. I submitted the patch
> but the feed back was that debugfs_create_bool() has a stupid API and
> should take a pointer to a bool. I said that yes, probably that is true
> but only two places use the current API incorrectly and I fixed the
> other place as well.
>
> I assumed that both my patches would be merged and the person who cared
> about API would fix the API but neither of my fixes were applied.
>
> diff --git a/lib/dma-debug.c b/lib/dma-debug.c
> index 518aea7..66ce414 100644
> --- a/lib/dma-debug.c
> +++ b/lib/dma-debug.c
> @@ -78,7 +78,7 @@ static LIST_HEAD(free_entries);
> static DEFINE_SPINLOCK(free_entries_lock);
>
> /* Global disable flag - will be set in case of an error */
> -static bool global_disable __read_mostly;
> +static u32 global_disable __read_mostly;
>
> /* Global error count */
> static u32 error_count;
> @@ -657,7 +657,7 @@ static int dma_debug_fs_init(void)
>
> global_disable_dent = debugfs_create_bool("disabled", 0444,
> dma_debug_dent,
> - (u32 *)&global_disable);
> + &global_disable);
> if (!global_disable_dent)
> goto out_err;
>
>
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