Hi, Dan: Dan Carpenter <dan.carpenter@xxxxxxxxxx> 於 2024年9月12日 週四 下午4:45寫道： > > In mtk_crtc_create(), if the call to mbox_request_channel() fails then we > set the "mtk_crtc->cmdq_client.chan" pointer to NULL. In that situation, > we do not call cmdq_pkt_create(). > > During the cleanup, we need to check if the "mtk_crtc->cmdq_client.chan" > is NULL first before calling cmdq_pkt_destroy(). Calling > cmdq_pkt_destroy() is unnecessary if we didn't call cmdq_pkt_create() and > it will result in a NULL pointer dereference. Applied to mediatek-drm-fixes [1], thanks. [1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes Regards, Chun-Kuang. > > Fixes: 7627122fd1c0 ("drm/mediatek: Add cmdq_handle in mtk_crtc") > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > --- > drivers/gpu/drm/mediatek/mtk_crtc.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c > index 175b00e5a253..c15013792583 100644 > --- a/drivers/gpu/drm/mediatek/mtk_crtc.c > +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c > @@ -127,9 +127,8 @@ static void mtk_crtc_destroy(struct drm_crtc *crtc) > > mtk_mutex_put(mtk_crtc->mutex); > #if IS_REACHABLE(CONFIG_MTK_CMDQ) > - cmdq_pkt_destroy(&mtk_crtc->cmdq_client, &mtk_crtc->cmdq_handle); > - > if (mtk_crtc->cmdq_client.chan) { > + cmdq_pkt_destroy(&mtk_crtc->cmdq_client, &mtk_crtc->cmdq_handle); > mbox_free_channel(mtk_crtc->cmdq_client.chan); > mtk_crtc->cmdq_client.chan = NULL; > } > -- > 2.45.2 >
