From: Wayne Lin wayne.lin@amd.com

stable inclusion from stable-v4.19.315 commit 09909f515032fa80b921fd3118efe66b185d10fd category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4M5 CVE: CVE-2023-52753

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v...

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[ Upstream commit b1904ed480cee3f9f4036ea0e36d139cb5fee2d6 ]

[Why & How] Check whether assigned timing generator is NULL or not before accessing its funcs to prevent NULL dereference.

Reviewed-by: Jun Lei jun.lei@amd.com Acked-by: Hersen Wu hersenxs.wu@amd.com Signed-off-by: Wayne Lin wayne.lin@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Wenyu Huang huangwenyu5@huawei.com --- drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c index fdcc8ab19bf3..25b8a8f93382 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c @@ -281,7 +281,7 @@ uint32_t dc_stream_get_vblank_counter(const struct dc_stream_state *stream) for (i = 0; i < MAX_PIPES; i++) { struct timing_generator *tg = res_ctx->pipe_ctx[i].stream_res.tg;

- if (res_ctx->pipe_ctx[i].stream != stream) + if (res_ctx->pipe_ctx[i].stream != stream || !tg) continue;

return tg->funcs->get_frame_count(tg); @@ -305,7 +305,7 @@ bool dc_stream_get_scanoutpos(const struct dc_stream_state *stream, for (i = 0; i < MAX_PIPES; i++) { struct timing_generator *tg = res_ctx->pipe_ctx[i].stream_res.tg;

- if (res_ctx->pipe_ctx[i].stream != stream) + if (res_ctx->pipe_ctx[i].stream != stream || !tg) continue;

tg->funcs->get_scanoutpos(tg,