linux-kernel - [PATCH] drm/amd/display: Fix pointer dereferenced before checking

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Message-ID: <1649310731-15934-1-git-send-email-baihaowen@meizu.com>
Date:   Thu, 7 Apr 2022 13:52:11 +0800
From:   Haowen Bai <baihaowen@...zu.com>
To:     Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>
CC:     Haowen Bai <baihaowen@...zu.com>, <amd-gfx@...ts.freedesktop.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/amd/display: Fix pointer dereferenced before checking

The pointer dc is dereferencing pointer plane_state before plane_state
is being null checked. Fix this by assigning plane_state->ctx->dc to
dc only if plane_state is not NULL, otherwise just NULL.

Signed-off-by: Haowen Bai <baihaowen@...zu.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 50820e79d3c4..ee22f4422d26 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -3211,7 +3211,7 @@ void dcn10_update_pending_status(struct pipe_ctx *pipe_ctx)
 	struct dc_plane_state *plane_state = pipe_ctx->plane_state;
 	struct timing_generator *tg = pipe_ctx->stream_res.tg;
 	bool flip_pending;
-	struct dc *dc = plane_state->ctx->dc;
+	struct dc *dc = plane_state ? plane_state->ctx->dc : NULL;
 
 	if (plane_state == NULL)
 		return;
-- 
2.7.4