From: Imre Deak <imre.deak@intel.com>
Date: Wed, 19 Jul 2017 14:43:28 +0300
Subject: [PATCH] drm/mst: Fix error handling during MST sideband message
reception
References: bnc#1060662
Patch-mainline: v4.12.4
Git-commit: 448421b5e93b9177c5698f0cf6f5e72d2995eeca
commit 448421b5e93b9177c5698f0cf6f5e72d2995eeca upstream.
Handle any error due to partial reads, timeouts etc. to avoid parsing
uninitialized data subsequently. Also bail out if the parsing itself
fails.
Cc: Dave Airlie <airlied@redhat.com>
Cc: Lyude <lyude@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude <lyude@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-2-imre.deak@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index d3fc7e4e85b7..025c406f2744 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2196,11 +2196,17 @@ static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
replyblock, len);
if (ret != len) {
- DRM_DEBUG_KMS("failed to read a chunk\n");
+ DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
+ len, ret);
+ return;
}
+
ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
- if (ret == false)
+ if (!ret) {
DRM_DEBUG_KMS("failed to build sideband msg\n");
+ return;
+ }
+
curreply += len;
replylen -= len;
}
--
2.14.2