Messages in this thread | | | Date | Wed, 23 Nov 2022 10:15:25 +0100 | Subject | Re: [PATCH v2] drm/mediatek: Clean dangling pointer on bind error path | From | AngeloGioacchino Del Regno <> |
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Il 22/11/22 15:39, Nícolas F. R. A. Prado ha scritto: > mtk_drm_bind() can fail, in which case drm_dev_put() is called, > destroying the drm_device object. However a pointer to it was still > being held in the private object, and that pointer would be passed along > to DRM in mtk_drm_sys_prepare() if a suspend were triggered at that > point, resulting in a panic. Clean the pointer when destroying the > object in the error path to prevent this from happening. > > Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.") > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> > > --- > > Changes in v2: > - Added Fixes tag > > drivers/gpu/drm/mediatek/mtk_drm_drv.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c > index 39a42dc8fb85..a21ff1b3258c 100644 > --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c > +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c > @@ -514,6 +514,7 @@ static int mtk_drm_bind(struct device *dev) > err_deinit: > mtk_drm_kms_deinit(drm); > err_free: > + private->drm = NULL;
Sorry for not noticing that in v1, but I've rechecked this function and, while this commit does indeed actually solve the described issue, I think it's incomplete.
A few lines before, we have a loop that sets
private->all_drm_private[i]->drm = drm;
...so here you should do...
private->drm = NULL;
while (i--) /* a for loop will also do, your choice */ private->all_drm_private[i]->drm = NULL; That makes sure that you cleanup *everything* :-)
Cheers, Angelo
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