Re: [PATCH] omap: resource: Fix race in register_resource()

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On Thu, Sep 17, 2009 at 4:32 PM, Mike Chan <mike@xxxxxxxxxxx> wrote:
> Checking if the resource is already registered and adding to the list
> must be atomic or bad things can happen.
>
> Signed-off-by: Mike Chan <mike@xxxxxxxxxxx>
> ---
>  arch/arm/plat-omap/resource.c |   13 ++++++++-----
>  1 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
> index 111020a..4631912 100644
> --- a/arch/arm/plat-omap/resource.c
> +++ b/arch/arm/plat-omap/resource.c
> @@ -255,6 +255,7 @@ int resource_refresh(void)
>  */
>  int resource_register(struct shared_resource *resp)
>  {
> +       int ret = 0;
>        if (!resp)
>                return -EINVAL;
>
> @@ -262,12 +263,13 @@ int resource_register(struct shared_resource *resp)
>                return -EINVAL;
>
>        /* Verify that the resource is not already registered */
> -       if (resource_lookup(resp->name))
> -               return -EEXIST;
> +       down(&res_mutex);
> +       if (_resource_lookup(resp->name))
> +               ret = -EEXIST;
> +               goto out;
>
>        INIT_LIST_HEAD(&resp->users_list);
>
> -       down(&res_mutex);
>        /* Add the resource to the resource list */
>        list_add(&resp->node, &res_list);
>
> @@ -275,10 +277,11 @@ int resource_register(struct shared_resource *resp)
>        if (resp->ops->init)
>                resp->ops->init(resp);
>
> -       up(&res_mutex);
>        pr_debug("resource: registered %s\n", resp->name);
>
> -       return 0;
> +out:
> +       up(&res_mutex);
> +       return ret;
>  }
>  EXPORT_SYMBOL(resource_register);
>
> --
> 1.5.4.5
>
>

Kevin, this should be based off of your pm branch (2.6.30?)

-- Mike
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