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authorXiaomeng Tong <xiam0nd.tong@gmail.com>2022-03-27 14:15:16 +0800
committerJyri Sarha <jyri.sarha@iki.fi>2022-03-29 13:58:58 +0300
commit8b917cbe38e9b0d002492477a9fc2bfee2412ce4 (patch)
tree3006370343f5fb7cae677ba80fbe1e412a95407d
parentbdef417d84536715145f6dc9cc3275c46f26295a (diff)
downloadlinux-8b917cbe38e9b0d002492477a9fc2bfee2412ce4.tar.bz2
tilcdc: tilcdc_external: fix an incorrect NULL check on list iterator
The bug is here: if (!encoder) { The list iterator value 'encoder' will *always* be set and non-NULL by 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 original variable 'encoder' as a dedicated pointer to point to the found element. Cc: stable@vger.kernel.org Fixes: ec9eab097a500 ("drm/tilcdc: Add drm bridge support for attaching drm bridge drivers") Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com> Reviewed-by: Jyri Sarha <jyri.sarha@iki.fi> Tested-by: Jyri Sarha <jyri.sarha@iki.fi> Signed-off-by: Jyri Sarha <jyri.sarha@iki.fi> Link: https://patchwork.freedesktop.org/patch/msgid/20220327061516.5076-1-xiam0nd.tong@gmail.com
-rw-r--r--drivers/gpu/drm/tilcdc/tilcdc_external.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_external.c b/drivers/gpu/drm/tilcdc/tilcdc_external.c
index 7594cf6e186e..3b86d002ef62 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_external.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_external.c
@@ -60,11 +60,13 @@ struct drm_connector *tilcdc_encoder_find_connector(struct drm_device *ddev,
int tilcdc_add_component_encoder(struct drm_device *ddev)
{
struct tilcdc_drm_private *priv = ddev->dev_private;
- struct drm_encoder *encoder;
+ struct drm_encoder *encoder = NULL, *iter;
- list_for_each_entry(encoder, &ddev->mode_config.encoder_list, head)
- if (encoder->possible_crtcs & (1 << priv->crtc->index))
+ list_for_each_entry(iter, &ddev->mode_config.encoder_list, head)
+ if (iter->possible_crtcs & (1 << priv->crtc->index)) {
+ encoder = iter;
break;
+ }
if (!encoder) {
dev_err(ddev->dev, "%s: No suitable encoder found\n", __func__);