Re: [PATCH next] drm/amd/display: Fix possible NULL dereference in dc_dmub_srv_cmd_run_list()

[Hamza Mahfooz]

On 4/26/23 15:24, Harshit Mogalapalli wrote:

We have a NULL check for 'dc_dmub_srv' in dc_dmub_srv_cmd_run_list()
but we are dereferencing it before checking.

Fix this moving the dereference next to NULL check.

This issue is found with Smatch(static analysis tool).

Fixes: e97cc04fe0fb ("drm/amd/display: refactor dmub commands into single 
function")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapa...@oracle.com>

Applied, thanks!

---
Only compile tested.
---
  drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c 
b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
index d15ec32243e2..62d3473c32bc 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -125,7 +125,7 @@ bool dc_dmub_srv_cmd_run(struct dc_dmub_srv *dc_dmub_srv, 
union dmub_rb_cmd *cmd

bool dc_dmub_srv_cmd_run_list(struct dc_dmub_srv *dc_dmub_srv, unsigned int count, union dmub_rb_cmd *cmd_list, enum dm_dmub_wait_type wait_type)

  {
-       struct dc_context *dc_ctx = dc_dmub_srv->ctx;
+       struct dc_context *dc_ctx;
        struct dmub_srv *dmub;
        enum dmub_status status;
        int i;
@@ -133,6 +133,7 @@ bool dc_dmub_srv_cmd_run_list(struct dc_dmub_srv 
*dc_dmub_srv, unsigned int coun
        if (!dc_dmub_srv || !dc_dmub_srv->dmub)
                return false;

+ dc_ctx = dc_dmub_srv->ctx;

        dmub = dc_dmub_srv->dmub;

for (i = 0 ; i < count; i++) {

--
Hamza