LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Sean Paul <seanpaul@chromium.org>
To: Emil Lundmark <lndmrk@chromium.org>
Cc: dri-devel@lists.freedesktop.org, Dave Airlie <airlied@redhat.com>,
	Sean Paul <seanpaul@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm: udl: Destroy framebuffer only if it was initialized
Date: Fri, 20 Apr 2018 09:55:32 -0400	[thread overview]
Message-ID: <20180420135532.GH73214@art_vandelay> (raw)
In-Reply-To: <20180420115001.161745-1-lndmrk@chromium.org>

On Fri, Apr 20, 2018 at 01:50:01PM +0200, Emil Lundmark wrote:
> This fixes a NULL pointer dereference that can happen if the UDL
> driver is unloaded before the framebuffer is initialized. This can
> happen e.g. if the USB device is unplugged right after it was plugged
> in.
> 

JFYI, in future, if someone makes a suggestion on how to fix a bug, it's good
practice to add a Suggested-by tag to give credit.

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> Signed-off-by: Emil Lundmark <lndmrk@chromium.org>
> ---
>  drivers/gpu/drm/udl/udl_fb.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
> index 2ebdc6d5a76e..5754e37f741b 100644
> --- a/drivers/gpu/drm/udl/udl_fb.c
> +++ b/drivers/gpu/drm/udl/udl_fb.c
> @@ -426,9 +426,11 @@ static void udl_fbdev_destroy(struct drm_device *dev,
>  {
>  	drm_fb_helper_unregister_fbi(&ufbdev->helper);
>  	drm_fb_helper_fini(&ufbdev->helper);
> -	drm_framebuffer_unregister_private(&ufbdev->ufb.base);
> -	drm_framebuffer_cleanup(&ufbdev->ufb.base);
> -	drm_gem_object_put_unlocked(&ufbdev->ufb.obj->base);
> +	if (ufbdev->ufb.obj) {
> +		drm_framebuffer_unregister_private(&ufbdev->ufb.base);
> +		drm_framebuffer_cleanup(&ufbdev->ufb.base);
> +		drm_gem_object_put_unlocked(&ufbdev->ufb.obj->base);
> +	}
>  }
>  
>  int udl_fbdev_init(struct drm_device *dev)
> -- 
> 2.17.0.484.g0c8726318c-goog
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS

  reply	other threads:[~2018-04-20 13:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-20 11:50 Emil Lundmark
2018-04-20 13:55 ` Sean Paul [this message]
2018-04-24 13:04   ` Daniel Vetter
2018-04-25 22:56     ` Stéphane Marchesin
2018-04-26  9:50       ` Daniel Vetter
2018-05-28 14:27 ` [PATCH v2] " Emil Lundmark
2018-05-29  6:46   ` Daniel Vetter
2018-09-10 14:23   ` Sean Paul

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180420135532.GH73214@art_vandelay \
    --to=seanpaul@chromium.org \
    --cc=airlied@redhat.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lndmrk@chromium.org \
    --subject='Re: [PATCH] drm: udl: Destroy framebuffer only if it was initialized' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).