linux-kernel - Re: [PATCH] pstore/ram: Avoid possible failure of dummy device unregister

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Message-ID: <CAGXu5j+Oi_2SyUb=pZ37PtGyPCvuZqnxAaGKDMiTsO0qWE6Rtg@mail.gmail.com>
Date:   Thu, 14 Feb 2019 08:22:32 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Yue Hu <zbestahu@...il.com>
Cc:     Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pstore/ram: Avoid possible failure of dummy device unregister

On Thu, Feb 14, 2019 at 3:31 AM Yue Hu <zbestahu@...il.com> wrote:
>
> From 08ac260f36b4c11eb33fa58466462a5e1027bdb3 Mon Sep 17 00:00:00 2001
> From: Yue Hu <zbestahu@...il.com>
> Date: Thu, 14 Feb 2019 19:34:16 +0800
> Subject: [PATCH] pstore/ram: Avoid possible failure of dummy device unregister
>
> If create dummy platform device failed, dummy variable should not
> been set as NULL. Because the following platform_device_unregister()
> will judge if the dummy is NULL or not, if dummy is NULL nothing
> happen for unregister flow.
>
> Signed-off-by: Yue Hu <zbestahu@...il.com>

I've gotten this email a few times today. :)

I already replied that this isn't what we want to do: we have to mark
it NULL since prior to that it was an ERR_PTR, and will break the
unregister.

-Kees

> ---
>  fs/pstore/ram.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 4a06675..61bc573 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -994,7 +994,6 @@ static void __init ramoops_register_dummy(void)
>         if (IS_ERR(dummy)) {
>                 pr_info("could not create platform device: %ld\n",
>                         PTR_ERR(dummy));
> -               dummy = NULL;
>                 ramoops_unregister_dummy();
>         }
>  }
> --
> 1.9.1
>


-- 
Kees Cook