diff mbox series

[4.19,120/338] drm/amd/display: Fix a NULL pointer dereference in amdgpu_dm_connector_add_common_modes()

Message ID 20220414110842.320599156@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg KH April 14, 2022, 1:10 p.m. UTC 
From: Zhou Qingyang <zhou1615@umn.edu>

[ Upstream commit 588a70177df3b1777484267584ef38ab2ca899a2 ]

In amdgpu_dm_connector_add_common_modes(), amdgpu_dm_create_common_mode()
is assigned to mode and is passed to drm_mode_probed_add() directly after
that. drm_mode_probed_add() passes &mode->head to list_add_tail(), and
there is a dereference of it in list_add_tail() without recoveries, which
could lead to NULL pointer dereference on failure of
amdgpu_dm_create_common_mode().

Fix this by adding a NULL check of mode.

This bug was found by a static analyzer.

Builds with 'make allyesconfig' show no new warnings,
and our static analyzer no longer warns about this code.

Fixes: e7b07ceef2a6 ("drm/amd/display: Merge amdgpu_dm_types and amdgpu_dm")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

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 ed02bb6b2cd0..b2835cd41d3e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3593,6 +3593,9 @@  static void amdgpu_dm_connector_add_common_modes(struct drm_encoder *encoder,
 		mode = amdgpu_dm_create_common_mode(encoder,
 				common_modes[i].name, common_modes[i].w,
 				common_modes[i].h);
+		if (!mode)
+			continue;
+
 		drm_mode_probed_add(connector, mode);
 		amdgpu_dm_connector->num_modes++;
 	}