Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932771Ab0GTV3e (ORCPT ); Tue, 20 Jul 2010 17:29:34 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:33742 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932597Ab0GTV3c convert rfc822-to-8bit (ORCPT ); Tue, 20 Jul 2010 17:29:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=Te65JlxXIR3Co2kLnW9Ig+OS0XeMsrPcunDgKSHp49W6EfEHbwgOnp9ynFzbmEP62a jSW73minpxiQx/ec++Ae3eoxUWinKKA0Ntv1c1bVHZ8TnT9YbtiCmLuslL4hDwjVuHaC fq1ddbkculgLRkxOW/rqlnYmTOUcBo8rYaiKI= MIME-Version: 1.0 In-Reply-To: References: <20100720014251.46b91cdd@mad-cat.localdomain> Date: Tue, 20 Jul 2010 17:29:31 -0400 Message-ID: Subject: Re: drivers/gpu/drm/radeon/r600_blit.c: fix possible NULL pointer derefernce From: Alex Deucher To: "Alexander Y. Fomichev" Cc: Dave Airlie , Robert Noland , Matt Turner , Jerome Glisse , akpm@linux-foundation.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3039 Lines: 92 On Tue, Jul 20, 2010 at 5:07 PM, Alexander Y. Fomichev wrote: > On Wed, Jul 21, 2010 at 1:00 AM, Alex Deucher wrote: >> On Tue, Jul 20, 2010 at 4:13 PM, Alexander Y. Fomichev >> wrote: >>> On Tue, Jul 20, 2010 at 9:37 PM, Alex Deucher wrote: >>>> On Mon, Jul 19, 2010 at 5:42 PM, Alexander Y. Fomichev >>>> wrote: >>>>> This patch fix possible NULL pointer dereference when >>>>> r600_prepare_blit_copy tries to fill dev_priv->blit_vb->file_priv >>>>> without check of dev_priv->blit_vb. dev_priv->blit_vb should be >>>>> filled by r600_nomm_get_vb but latest can fail with EAGAIN. >>>>> Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=16375 >>>>> >>>>> --- >>>>> ?drivers/gpu/drm/radeon/r600_blit.c | ? ?2 ++ >>>>> ?1 files changed, 2 insertions(+), 0 deletions(-) >>>>> >>>>> diff --git a/drivers/gpu/drm/radeon/r600_blit.c b/drivers/gpu/drm/radeon/r600_blit.c >>>>> index f4fb88e..0df4a2b 100644 >>>>> --- a/drivers/gpu/drm/radeon/r600_blit.c >>>>> +++ b/drivers/gpu/drm/radeon/r600_blit.c >>>>> @@ -541,6 +541,8 @@ r600_prepare_blit_copy(struct drm_device *dev, struct drm_file *file_priv) >>>>> ? ? ? ?DRM_DEBUG("\n"); >>>>> >>>>> ? ? ? ?r600_nomm_get_vb(dev); >>>>> + ? ? ? if (!dev_priv->blit_vb) >>>>> + ? ? ? ? ? ? ? return; >>>> >>>> r600_prepare_blit_copy returns an int so something like this would be better: >>>> --- a/drivers/gpu/drm/radeon/r600_blit.c >>>> +++ b/drivers/gpu/drm/radeon/r600_blit.c >>>> @@ -539,8 +539,10 @@ r600_prepare_blit_copy(struct drm_device *dev, >>>> struct drm_file *file_priv) >>>> ?{ >>>> ? ? ? ?drm_radeon_private_t *dev_priv = dev->dev_private; >>>> ? ? ? ?DRM_DEBUG("\n"); >>>> + ? ? ? int ret = r600_nomm_get_vb(dev); >>>> >>>> - ? ? ? r600_nomm_get_vb(dev); >>>> + ? ? ? if (ret) >>>> + ? ? ? ? ? ? ? return ret; >>>> >>>> ? ? ? ?dev_priv->blit_vb->file_priv = file_priv; >>>> >>>> >>>> Alex >>>> >>>>> >>>>> ? ? ? ?dev_priv->blit_vb->file_priv = file_priv; >>>>> >>>>> -- >>>>> 1.7.1.1 >>>>> >>>> >>> >>> i haven't any preferneces, the only thing is - it would be logical >>> to have every check in common style, so other cases >>> (r600_blit_copy, r600_blit_swap) should be fixed, nop? >> >> Those are void functions so there's nothing to return. > > i mean both of them call r600_nomm_get_vb and both of them > check if (!dev_priv->blit_vb), not return ?value.I mean would be > logical to check it the same way everytime r600_nomm_get_vb > gets called. yeah, either way. You just need to return an error in r600_prepare_blit_copy. Alex > >> Alex >> >>> >>> -- >>> Best regards. >>> ? ? ?? Alexander Y. Fomichev >>> >> > > > > -- > Best regards. > ? ? ?? Alexander Y. Fomichev > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/