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| author | Xiaomeng Tong <xiam0nd.tong@gmail.com> | 2022-03-27 13:53:55 +0800 |
|---|---|---|
| committer | Philippe Cornu <philippe.cornu@foss.st.com> | 2022-04-07 10:26:59 +0200 |
| commit | 2e6c86be0e57079d1fb6c7c7e5423db096d0548a (patch) | |
| tree | 2f1e33cc53b862be579e1952d918bdeebbc8be26 /drivers/gpu/drm/stm | |
| parent | c8d4c18bfbc4ab467188dbe45cc8155759f49d9e (diff) | |
| download | lwn-2e6c86be0e57079d1fb6c7c7e5423db096d0548a.tar.gz lwn-2e6c86be0e57079d1fb6c7c7e5423db096d0548a.zip | |
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.c | 16 |
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); |