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 831D3266F17; Tue, 8 Apr 2025 11:52:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744113159; cv=none; b=OTNKZRmhu2xkeVMWjbkQFtdw+258zlziaVdKlZWX3mmkEOpE/tKW0K7OWn0qgiwauJ+CvxlCK/yzBzN0ETGQRfLAP8JjTpEPM2lk1zd7PQJ8JVBHJiozN8MFLHRiek8I9I8fc0jR0fVgQRZIhR4g+tB9qQJpebRZ+ier5s/CQlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744113159; c=relaxed/simple; bh=+67/diASUDLM+eJq08PV2mIQkkr1mAkmGXloTy6wJAA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Lp8PO6DuO7EShZo5JQplMtA9dFoFjRksRwNeLTJV7Ktcz6ycnTV3h4+vXQVP8TI/6RLKM5d0VOPldgHaZ8AfXgmFa4gN8Lfjakx8593M5S0xZ99c9JDN8TcuKlNFGKUwQc40PfyvOt4TLN6Tu2HlW4ZjvlCMISmNVReMWAlWZm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ebhk/CI5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ebhk/CI5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F117C4CEE5; Tue, 8 Apr 2025 11:52:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744113158; bh=+67/diASUDLM+eJq08PV2mIQkkr1mAkmGXloTy6wJAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ebhk/CI5bO2CJ5uKInZRXj0Cwad3IRmGSuCx4RgFSSw6CBHB9NHqohrB+e3K4S9zz p6PoKIVbjGPcS39vx8pbABZvXgiI99KYi3QhiBhF0VsJt/QaxkoOA1CkG0WCGyVOsD O1PCLd7q2LYRRvpNKvmEZOOB/D0+4rrB7xIiVzc0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Douglas Anderson , CK Hu , Chun-Kuang Hu , Sasha Levin Subject: [PATCH 6.6 054/268] drm/mediatek: dp: drm_err => dev_err in HPD path to avoid NULL ptr Date: Tue, 8 Apr 2025 12:47:45 +0200 Message-ID: <20250408104829.957778744@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104828.499967190@linuxfoundation.org> References: <20250408104828.499967190@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Douglas Anderson [ Upstream commit 106a6de46cf4887d535018185ec528ce822d6d84 ] The function mtk_dp_wait_hpd_asserted() may be called before the `mtk_dp->drm_dev` pointer is assigned in mtk_dp_bridge_attach(). Specifically it can be called via this callpath: - mtk_edp_wait_hpd_asserted - [panel probe] - dp_aux_ep_probe Using "drm" level prints anywhere in this callpath causes a NULL pointer dereference. Change the error message directly in mtk_dp_wait_hpd_asserted() to dev_err() to avoid this. Also change the error messages in mtk_dp_parse_capabilities(), which is called by mtk_dp_wait_hpd_asserted(). While touching these prints, also add the error code to them to make future debugging easier. Fixes: 7eacba9a083b ("drm/mediatek: dp: Add .wait_hpd_asserted() for AUX bus") Signed-off-by: Douglas Anderson Reviewed-by: CK Hu Link: https://patchwork.kernel.org/project/dri-devel/patch/20250116094249.1.I29b0b621abb613ddc70ab4996426a3909e1aa75f@changeid/ Signed-off-by: Chun-Kuang Hu Signed-off-by: Sasha Levin --- drivers/gpu/drm/mediatek/mtk_dp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index be4de26c77f91..199527643093a 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -1648,7 +1648,7 @@ static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp) ret = drm_dp_dpcd_readb(&mtk_dp->aux, DP_MSTM_CAP, &val); if (ret < 1) { - drm_err(mtk_dp->drm_dev, "Read mstm cap failed\n"); + dev_err(mtk_dp->dev, "Read mstm cap failed: %zd\n", ret); return ret == 0 ? -EIO : ret; } @@ -1658,7 +1658,7 @@ static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp) DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0, &val); if (ret < 1) { - drm_err(mtk_dp->drm_dev, "Read irq vector failed\n"); + dev_err(mtk_dp->dev, "Read irq vector failed: %zd\n", ret); return ret == 0 ? -EIO : ret; } @@ -1941,7 +1941,7 @@ static int mtk_dp_wait_hpd_asserted(struct drm_dp_aux *mtk_aux, unsigned long wa ret = mtk_dp_parse_capabilities(mtk_dp); if (ret) { - drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n"); + dev_err(mtk_dp->dev, "Can't parse capabilities: %d\n", ret); return ret; } -- 2.39.5