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From: Kees Cook <keescook@chromium.org>
To: Juerg Haefliger <juerg.haefliger@hpe.com>,
	Greg KH <gregkh@linuxfoundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] lkdtm: Fix Oops when unloading the module
Date: Thu, 19 Jan 2017 14:03:11 -0800	[thread overview]
Message-ID: <CAGXu5jL=tBcpoHx6vDetPSwB2CewwqOJNbVr=DJTbXJFXPVLDw@mail.gmail.com> (raw)
In-Reply-To: <20170119104013.8073-1-juerg.haefliger@hpe.com>

On Thu, Jan 19, 2017 at 2:40 AM, Juerg Haefliger
<juerg.haefliger@hpe.com> wrote:
> No jprobe is registered when the module is loaded without specifying a
> crashpoint that uses a jprobe. At the moment, we unconditionally try to
> unregister the jprobe on module unload which results in an Oops. Add a
> check to fix this.
>
> Signed-off-by: Juerg Haefliger <juerg.haefliger@hpe.com>

Ah-ha, nice catch, thanks!

Acked-by: Kees Cook <keescook@chromium.org>

Greg, can you please add this to your tree when you get a chance?

-Kees

> ---
>  drivers/misc/lkdtm_core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
> index 7eeb71a75549..4d44084071d8 100644
> --- a/drivers/misc/lkdtm_core.c
> +++ b/drivers/misc/lkdtm_core.c
> @@ -535,7 +535,9 @@ static void __exit lkdtm_module_exit(void)
>         /* Handle test-specific clean-up. */
>         lkdtm_usercopy_exit();
>
> -       unregister_jprobe(lkdtm_jprobe);
> +       if (lkdtm_jprobe != NULL)
> +               unregister_jprobe(lkdtm_jprobe);
> +
>         pr_info("Crash point unregistered\n");
>  }
>
> --
> 2.11.0
>



-- 
Kees Cook
Nexus Security

  reply	other threads:[~2017-01-19 22:03 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-19 10:40 [PATCH] lkdtm: Fix Oops when unloading the module Juerg Haefliger
2017-01-19 22:03 ` Kees Cook [this message]
2017-01-20 10:01   ` Greg KH

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