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Wed, 12 Feb 2025 00:52:37 -0800 (PST) Date: Wed, 12 Feb 2025 09:52:35 +0100 From: =?iso-8859-1?Q?Jos=E9_Exp=F3sito?= To: Thomas Zimmermann Cc: louis.chauvet@bootlin.com, hamohammed.sa@gmail.com, simona@ffwll.ch, melissa.srw@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 01/15] drm/vkms: Fix use after free and double free on init error Message-ID: References: <20250211110912.15409-1-jose.exposito89@gmail.com> <20250211110912.15409-2-jose.exposito89@gmail.com> <428f88f2-1f30-4018-8113-1c4716288789@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <428f88f2-1f30-4018-8113-1c4716288789@suse.de> Hi Thomas, On Tue, Feb 11, 2025 at 03:33:55PM +0100, Thomas Zimmermann wrote: > Hi > > Am 11.02.25 um 12:08 schrieb José Expósito: > > If the driver initialization fails, the vkms_exit() function might > > access an uninitialized or freed default_config pointer and it might > > double free it. > > > > Fix both possible errors by initializing default_config only when the > > driver initialization succeeded. > > Could you send this patch separately, so that it can go into drm-misc-fixes > quickly? Sure, I just sent it as a separate patch. Thanks, Jose > Best regards > Thomas > > > > > Reported-by: Louis Chauvet > > Link: https://lore.kernel.org/all/Z5uDHcCmAwiTsGte@louis-chauvet-laptop/ > > Fixes: 2df7af93fdad ("drm/vkms: Add vkms_config type") > > Signed-off-by: José Expósito > > --- > > drivers/gpu/drm/vkms/vkms_drv.c | 15 +++++++++------ > > 1 file changed, 9 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c > > index 7c142bfc3bd9..b6de91134a22 100644 > > --- a/drivers/gpu/drm/vkms/vkms_drv.c > > +++ b/drivers/gpu/drm/vkms/vkms_drv.c > > @@ -235,17 +235,19 @@ static int __init vkms_init(void) > > if (!config) > > return -ENOMEM; > > - default_config = config; > > - > > config->cursor = enable_cursor; > > config->writeback = enable_writeback; > > config->overlay = enable_overlay; > > ret = vkms_create(config); > > - if (ret) > > + if (ret) { > > kfree(config); > > + return ret; > > + } > > - return ret; > > + default_config = config; > > + > > + return 0; > > } > > static void vkms_destroy(struct vkms_config *config) > > @@ -269,9 +271,10 @@ static void vkms_destroy(struct vkms_config *config) > > static void __exit vkms_exit(void) > > { > > - if (default_config->dev) > > - vkms_destroy(default_config); > > + if (!default_config) > > + return; > > + vkms_destroy(default_config); > > kfree(default_config); > > } > > -- > -- > Thomas Zimmermann > Graphics Driver Developer > SUSE Software Solutions Germany GmbH > Frankenstrasse 146, 90461 Nuernberg, Germany > GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman > HRB 36809 (AG Nuernberg) >