Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933571Ab0GUHGW (ORCPT ); Wed, 21 Jul 2010 03:06:22 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:58935 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933349Ab0GUHGR convert rfc822-to-8bit (ORCPT ); Wed, 21 Jul 2010 03:06:17 -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=hkDuQX2fqZK8i1r8ZZ9GZduDIFK8Pg/ha1pVmI/ZGBYNfVtSW6DHXV1Cy2z7bH3KB4 a0mgRZ7iW9MgFOE4Uwb9jfYcHEyJtmML1fhlKNEQf/R4MrEz8l9iOz9O3i3ByQsrMyiH bZN4feIimsvOnnw4yWd6BAQlfrgJGhwYUfJn8= MIME-Version: 1.0 In-Reply-To: References: <20100720014251.46b91cdd@mad-cat.localdomain> Date: Wed, 21 Jul 2010 11:06:15 +0400 Message-ID: Subject: Re: drivers/gpu/drm/radeon/r600_blit.c: fix possible NULL pointer derefernce From: "Alexander Y. Fomichev" To: Alex Deucher 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: 3298 Lines: 100 On Wed, Jul 21, 2010 at 1:29 AM, Alex Deucher wrote: > 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. uh-huh, i've missed > Alex > >> >>> Alex >>> >>>> >>>> -- >>>> Best regards. >>>> ? ? ?? Alexander Y. Fomichev >>>> >>> >> >> >> >> -- >> 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/