[PATCH 5.10/5.15/6.1 v2] drm/amd/display: set new_stream to NULL after release

[Roman Demidov <roman.demidov.nn@gmail.com>]

From: WenTao Liang <vulab@iscas.ac.cn>

commit 9fa26b9eed6195bf840f39ac183b9a6237548755 upstream.

In dm_update_crtc_state(), the skip_modeset path releases new_stream
via dc_stream_release() but does not set the pointer to NULL.

If a later error (e.g., color management failure) triggers the fail
label, the error path calls dc_stream_release() again on the same
dangling pointer, causing a double release and potential use-after-free.

Fix this by setting new_stream to NULL after the initial release.

Fixes: 9b690ef3c704 ("drm/amd/display: Avoid full modeset when not required")
Signed-off-by: WenTao Liang <vulab@iscas.ac.cn>
Reviewed-by: George Zhang <george.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Roman Demidov <roman.demidov.nn@gmail.com>
---
Backport fix for CVE-2026-68236
v2: Include version 5.15 in the patch, as Sasha Levin <sashal@kernel.org>
suggested.

 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index bb5e3a6086f2..deaf98957cb7 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -9293,6 +9293,7 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm,
 	/* Release extra reference */
 	if (new_stream)
 		 dc_stream_release(new_stream);
+	new_stream = NULL;
 
 	/*
 	 * We want to do dc stream updates that do not require a
-- 
2.53.0