From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EA181170E for ; Mon, 21 Aug 2023 19:50:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BA25C433C7; Mon, 21 Aug 2023 19:50:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692647452; bh=OYlNHeqgaZ8ZKIneDOaNIS064bRseQPY0XLl3sbQXCc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DAJnAURE1RJSsmSw63AjTgVKPeETImTRWaila+1kvVZVRmbeC1t/Y+EvWWzQXGYqm vnVdYpab8j/scQiCSKuTcHj9towepkgXZ4iG3TpC6BgEOsEzqE3SXh1tn2JawFl1Oy Xbk4JUQM4Ku63bQesiRyQdWVz1aYiLfMTb+Ddpyk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Dan Carpenter , Raphael Gallais-Pou , Philippe Cornu , Sasha Levin Subject: [PATCH 6.1 019/194] drm/stm: ltdc: fix late dereference check Date: Mon, 21 Aug 2023 21:39:58 +0200 Message-ID: <20230821194123.621614547@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230821194122.695845670@linuxfoundation.org> References: <20230821194122.695845670@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Raphael Gallais-Pou [ Upstream commit 898a9e3f56db9860ab091d4bf41b6caa99aafc3d ] In ltdc_crtc_set_crc_source(), struct drm_crtc was dereferenced in a container_of() before the pointer check. This could cause a kernel panic. Fix this smatch warning: drivers/gpu/drm/stm/ltdc.c:1124 ltdc_crtc_set_crc_source() warn: variable dereferenced before check 'crtc' (see line 1119) Reported-by: kernel test robot Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@intel.com/ Reported-by: Dan Carpenter Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@intel.com/ Signed-off-by: Raphael Gallais-Pou Acked-by: Philippe Cornu Signed-off-by: Philippe Cornu Link: https://patchwork.freedesktop.org/patch/msgid/20230515123818.93971-1-raphael.gallais-pou@foss.st.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/stm/ltdc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c index 03c6becda795c..b8be4c1db4235 100644 --- a/drivers/gpu/drm/stm/ltdc.c +++ b/drivers/gpu/drm/stm/ltdc.c @@ -1145,7 +1145,7 @@ static void ltdc_crtc_disable_vblank(struct drm_crtc *crtc) static int ltdc_crtc_set_crc_source(struct drm_crtc *crtc, const char *source) { - struct ltdc_device *ldev = crtc_to_ltdc(crtc); + struct ltdc_device *ldev; int ret; DRM_DEBUG_DRIVER("\n"); @@ -1153,6 +1153,8 @@ static int ltdc_crtc_set_crc_source(struct drm_crtc *crtc, const char *source) if (!crtc) return -ENODEV; + ldev = crtc_to_ltdc(crtc); + if (source && strcmp(source, "auto") == 0) { ldev->crc_active = true; ret = regmap_set_bits(ldev->regmap, LTDC_GCR, GCR_CRCEN); -- 2.40.1