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 607031FCCF6; Sun, 26 Jan 2025 14:56:18 +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=1737903378; cv=none; b=Enh+MTj3aeNu3UpmN34qw2hxYTiq3hiJ3mQ1AQFN9Yt2Z8/YdcglyMSMRUrMEEQsaTtCwMxCnLoP/XFmXNvccXdA6YJMCBBOHng9NQdmOSH+kMPp6L+frtmLFeLblF04nNzA1tPmgf7z+S72jNV1/5V4S3Q8sBKiQWoBo1CBjZ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737903378; c=relaxed/simple; bh=OAYQq0O94/PSvNgw2CG3m7XJBnsy9Nv0aKGnYADaU1w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=rvIZ82fxQaPXBG0MQJV5JyAxzTsru8d94BXR2wDheZUrYpf2UgJsiiyVNlWl6kfn14Oq5jpeyPOw749K9BIlwRtwryfxP+ZE8wRx/JjeMFcEpiQlELMVZOx7S6Nmac6B1wujNVpbJYUCzXG79nuMN2KFLK6Whzo84welX+Uf9lE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eS39qonB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eS39qonB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25FFFC4CEE3; Sun, 26 Jan 2025 14:56:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737903378; bh=OAYQq0O94/PSvNgw2CG3m7XJBnsy9Nv0aKGnYADaU1w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eS39qonBGDGAzX9w3KymNRfS3QZ/OhhrF41NS7xAx+UpesWpX8/jMPGUCD0z84qew gE/TeikZlOj31NRp2ItFh7WpmmqNYMqh++/bzEfQ8O/WxQIoBBpM30uBpyW/vf+14v F+6hcxi8s7k01GsXnxH+snYp4oE1yk4aAGDyBgMup1mgfOqT8lpMYBSy1g7GLql++0 BHDKa8cf7AtvpRR1OXbUelEiwxolhw4FuHaz7BQyiAzPoTXf6OFoyGiVyT8VDlgBTY AtNoLFcBZT4Xc5xjnzCMY8vZm1cKRL5TUbvKfL6szPhkPSjqq3tsPLiKXZ0SwRmLCM 7NQgBJblAOM6g== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dmitry Baryshkov , Maxime Ripard , Sasha Levin , maarten.lankhorst@linux.intel.com, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 6.6 03/17] drm/connector: add mutex to protect ELD from concurrent access Date: Sun, 26 Jan 2025 09:55:58 -0500 Message-Id: <20250126145612.937679-3-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250126145612.937679-1-sashal@kernel.org> References: <20250126145612.937679-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.74 Content-Transfer-Encoding: 8bit From: Dmitry Baryshkov [ Upstream commit df7c8e3dde37a9d81c0613285b43600f3cc70f34 ] The connector->eld is accessed by the .get_eld() callback. This access can collide with the drm_edid_to_eld() updating the data at the same time. Add drm_connector.eld_mutex to protect the data from concurrenct access. Individual drivers are not updated (to reduce possible issues while applying the patch), maintainers are to find a best suitable way to lock that mutex while accessing the ELD data. Reviewed-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20241206-drm-connector-eld-mutex-v2-1-c9bce1ee8bea@linaro.org Signed-off-by: Dmitry Baryshkov Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_connector.c | 1 + drivers/gpu/drm/drm_edid.c | 6 ++++++ include/drm/drm_connector.h | 5 ++++- 3 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 309aad5f0c808..35bed66214474 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -277,6 +277,7 @@ static int __drm_connector_init(struct drm_device *dev, INIT_LIST_HEAD(&connector->probed_modes); INIT_LIST_HEAD(&connector->modes); mutex_init(&connector->mutex); + mutex_init(&connector->eld_mutex); mutex_init(&connector->edid_override_mutex); connector->edid_blob_ptr = NULL; connector->epoch_counter = 0; diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index ee3fab115c4b5..ad872c61aac0e 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5499,7 +5499,9 @@ EXPORT_SYMBOL(drm_edid_get_monitor_name); static void clear_eld(struct drm_connector *connector) { + mutex_lock(&connector->eld_mutex); memset(connector->eld, 0, sizeof(connector->eld)); + mutex_unlock(&connector->eld_mutex); connector->latency_present[0] = false; connector->latency_present[1] = false; @@ -5530,6 +5532,8 @@ static void drm_edid_to_eld(struct drm_connector *connector, if (!drm_edid) return; + mutex_lock(&connector->eld_mutex); + mnl = get_monitor_name(drm_edid, &eld[DRM_ELD_MONITOR_NAME_STRING]); drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] ELD monitor %s\n", connector->base.id, connector->name, @@ -5590,6 +5594,8 @@ static void drm_edid_to_eld(struct drm_connector *connector, drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] ELD size %d, SAD count %d\n", connector->base.id, connector->name, drm_eld_size(eld), total_sad_count); + + mutex_unlock(&connector->eld_mutex); } static int _drm_edid_to_sad(const struct drm_edid *drm_edid, diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index d300fde6c1a47..b2e9dc02fa349 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -1764,8 +1764,11 @@ struct drm_connector { struct drm_encoder *encoder; #define MAX_ELD_BYTES 128 - /** @eld: EDID-like data, if present */ + /** @eld: EDID-like data, if present, protected by @eld_mutex */ uint8_t eld[MAX_ELD_BYTES]; + /** @eld_mutex: protection for concurrenct access to @eld */ + struct mutex eld_mutex; + /** @latency_present: AV delay info from ELD, if found */ bool latency_present[2]; /** -- 2.39.5