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[4.4,05/16] drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem

Message ID 20200423204014.784944-6-lee.jones@linaro.org
State Superseded
Headers show
Series [4.4,01/16] drm/msm: stop abusing dma_map/unmap for cache | expand

Commit Message

Lee Jones April 23, 2020, 8:40 p.m. UTC 
From: Joe Moriarty <joe.moriarty@oracle.com>

[ Upstream commit 22a07038c0eaf4d1315a493ce66dcd255accba19 ]

The Parfait (version 2.1.0) static code analysis tool found the
following NULL pointer derefernce problem.

- drivers/gpu/drm/drm_dp_mst_topology.c
The call to drm_dp_calculate_rad() in function drm_dp_port_setup_pdt()
could result in a NULL pointer being returned to port->mstb due to a
failure to allocate memory for port->mstb.

Signed-off-by: Joe Moriarty <joe.moriarty@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180212195144.98323-3-joe.moriarty@oracle.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
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Patch

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index f5229b083f8ea..abf5bd09de33b 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1036,10 +1036,12 @@  static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
 		lct = drm_dp_calculate_rad(port, rad);
 
 		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
-		port->mstb->mgr = port->mgr;
-		port->mstb->port_parent = port;
+		if (port->mstb) {
+			port->mstb->mgr = port->mgr;
+			port->mstb->port_parent = port;
 
-		send_link = true;
+			send_link = true;
+		}
 		break;
 	}
 	return send_link;