[PATCH][next] drm/amd/display: don't release dc->current_state if it is null

From: Colin King
Date: Sat Jun 29 2019 - 08:27:57 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Currently function construct calls destruct if the allocation of
dc->current_state fails, however, the destruct function will
attempt dereference dc->current_state when calling dc_release_state.
Avoid this null pointer dereference by checking if the pointer is
not null before calling dc_release_state.

Addresses-Coverity: ("Dereference after null check")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 18c775a950cc..0e1f132ae310 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -608,8 +608,10 @@ const struct dc_link_settings *dc_link_get_link_cap(

static void destruct(struct dc *dc)
{
- dc_release_state(dc->current_state);
- dc->current_state = NULL;
+ if (dc->current_state) {
+ dc_release_state(dc->current_state);
+ dc->current_state = NULL;
+ }

destroy_links(dc);

--
2.20.1