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authorXiaomeng Tong <xiam0nd.tong@gmail.com>2022-03-27 13:53:55 +0800
committerPhilippe Cornu <philippe.cornu@foss.st.com>2022-04-07 10:26:59 +0200
commit2e6c86be0e57079d1fb6c7c7e5423db096d0548a (patch)
tree2f1e33cc53b862be579e1952d918bdeebbc8be26 /drivers/gpu/drm/stm
parentc8d4c18bfbc4ab467188dbe45cc8155759f49d9e (diff)
stm: ltdc: fix two incorrect NULL checks on list iterator
The two bugs are here: if (encoder) { if (bridge && bridge->timings) The list iterator value 'encoder/bridge' will *always* be set and non-NULL by drm_for_each_encoder()/list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found. To fix the bug, use a new variable '*_iter' as the list iterator, while use the old variable 'encoder/bridge' as a dedicated pointer to point to the found element. Cc: stable@vger.kernel.org Fixes: 99e360442f223 ("drm/stm: Fix bus_flags handling") Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com> Acked-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com> Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220327055355.3808-1-xiam0nd.tong@gmail.com
Diffstat (limited to 'drivers/gpu/drm/stm')
-rw-r--r--drivers/gpu/drm/stm/ltdc.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 17cc050207f4..6bd45df8f5a7 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -869,8 +869,8 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
struct drm_device *ddev = crtc->dev;
struct drm_connector_list_iter iter;
struct drm_connector *connector = NULL;
- struct drm_encoder *encoder = NULL;
- struct drm_bridge *bridge = NULL;
+ struct drm_encoder *encoder = NULL, *en_iter;
+ struct drm_bridge *bridge = NULL, *br_iter;
struct drm_display_mode *mode = &crtc->state->adjusted_mode;
u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
u32 total_width, total_height;
@@ -880,15 +880,19 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
int ret;
/* get encoder from crtc */
- drm_for_each_encoder(encoder, ddev)
- if (encoder->crtc == crtc)
+ drm_for_each_encoder(en_iter, ddev)
+ if (en_iter->crtc == crtc) {
+ encoder = en_iter;
break;
+ }
if (encoder) {
/* get bridge from encoder */
- list_for_each_entry(bridge, &encoder->bridge_chain, chain_node)
- if (bridge->encoder == encoder)
+ list_for_each_entry(br_iter, &encoder->bridge_chain, chain_node)
+ if (br_iter->encoder == encoder) {
+ bridge = br_iter;
break;
+ }
/* Get the connector from encoder */
drm_connector_list_iter_begin(ddev, &iter);