Re: [PATCH 1/3] ipuv3-crtc: add remove action for devres data
On Tue, Apr 02, 2019 at 05:49:23PM +0200, Philipp Zabel wrote: > Hi Michael, > > On Tue, 2019-04-02 at 15:49 +0200, Michael Grzeschik wrote: > > The destroy function in drm_mode_config_cleanup will remove the objects > > in ipu-drm-core by calling its destroy functions if the bind function > > fails. The drm_crtc is also part of the devres allocated ipu_crtc > > object. The ipu_crtc object will already be cleaned up if the bind for > > the crtc fails. This leads drm_crtc_cleanup try to clean already freed > > memory. > > > > We fix this issue by adding the devres action ipu_crtc_remove_head which > > will remove its head from the objects in ipu-drm-core which then never > > calls its destroy function anymore. > > > > Signed-off-by: Michael Grzeschik > > --- > > drivers/gpu/drm/imx/ipuv3-crtc.c | 12 > > 1 file changed, 12 insertions(+) > > > > diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c > > b/drivers/gpu/drm/imx/ipuv3-crtc.c > > index ec3602ebbc1cd..fa1ee33a43d77 100644 > > --- a/drivers/gpu/drm/imx/ipuv3-crtc.c > > +++ b/drivers/gpu/drm/imx/ipuv3-crtc.c > > @@ -429,6 +429,14 @@ static int ipu_crtc_init(struct ipu_crtc *ipu_crtc, > > return ret; > > } > > > > +static void ipu_crtc_remove_head(void *data) > > +{ > > + struct ipu_crtc *ipu_crtc = data; > > + struct drm_crtc *crtc = &ipu_crtc->base; > > + > > + list_del(&crtc->head); > > I don't think reaching into drm_crtc internals like this is going to be > robust. Currently, this is either missing the rest of drm_crtc_cleanup, > or it will crash if drm_crtc_init_with_planes hasn't been called yet. > > I think you could call devm_add_action with a function that calls > drm_crtc_cleanup after drm_crtc_init_with_planes in ipu_crtc_init. > > Alternatively, the ipu_crtc allocation could be changed to kzalloc. It > would then have to freed manually in the drm_crtc_funcs->destroy > callback. Dirty secret of devm: You can't use it for any drm_ structure, because the lifetimes of those do not match the lifetimes of the underlying device. We'd need to tie the lifetimes of drm objects to drm_device. Noralf has some patches to move that forward. We'd need something like drm_dev_kzalloc which releases memory when drm_device is freed. Agreed that digging even deeper into the devm deadend is not a good idea. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
[PATCH 1/3] ipuv3-crtc: add remove action for devres data
The destroy function in drm_mode_config_cleanup will remove the objects in ipu-drm-core by calling its destroy functions if the bind function fails. The drm_crtc is also part of the devres allocated ipu_crtc object. The ipu_crtc object will already be cleaned up if the bind for the crtc fails. This leads drm_crtc_cleanup try to clean already freed memory. We fix this issue by adding the devres action ipu_crtc_remove_head which will remove its head from the objects in ipu-drm-core which then never calls its destroy function anymore. Signed-off-by: Michael Grzeschik --- drivers/gpu/drm/imx/ipuv3-crtc.c | 12 1 file changed, 12 insertions(+) diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c index ec3602ebbc1cd..fa1ee33a43d77 100644 --- a/drivers/gpu/drm/imx/ipuv3-crtc.c +++ b/drivers/gpu/drm/imx/ipuv3-crtc.c @@ -429,6 +429,14 @@ static int ipu_crtc_init(struct ipu_crtc *ipu_crtc, return ret; } +static void ipu_crtc_remove_head(void *data) +{ + struct ipu_crtc *ipu_crtc = data; + struct drm_crtc *crtc = &ipu_crtc->base; + + list_del(&crtc->head); +} + static int ipu_drm_bind(struct device *dev, struct device *master, void *data) { struct ipu_client_platformdata *pdata = dev->platform_data; @@ -440,6 +448,10 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data) if (!ipu_crtc) return -ENOMEM; + ret = devm_add_action(dev, ipu_crtc_remove_head, ipu_crtc); + if (ret) + return ret; + ipu_crtc->dev = dev; ret = ipu_crtc_init(ipu_crtc, pdata, drm); -- 2.20.1 ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH 1/3] ipuv3-crtc: add remove action for devres data
Hi Michael, On Tue, 2019-04-02 at 15:49 +0200, Michael Grzeschik wrote: > The destroy function in drm_mode_config_cleanup will remove the objects > in ipu-drm-core by calling its destroy functions if the bind function > fails. The drm_crtc is also part of the devres allocated ipu_crtc > object. The ipu_crtc object will already be cleaned up if the bind for > the crtc fails. This leads drm_crtc_cleanup try to clean already freed > memory. > > We fix this issue by adding the devres action ipu_crtc_remove_head which > will remove its head from the objects in ipu-drm-core which then never > calls its destroy function anymore. > > Signed-off-by: Michael Grzeschik > --- > drivers/gpu/drm/imx/ipuv3-crtc.c | 12 > 1 file changed, 12 insertions(+) > > diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c > b/drivers/gpu/drm/imx/ipuv3-crtc.c > index ec3602ebbc1cd..fa1ee33a43d77 100644 > --- a/drivers/gpu/drm/imx/ipuv3-crtc.c > +++ b/drivers/gpu/drm/imx/ipuv3-crtc.c > @@ -429,6 +429,14 @@ static int ipu_crtc_init(struct ipu_crtc *ipu_crtc, > return ret; > } > > +static void ipu_crtc_remove_head(void *data) > +{ > + struct ipu_crtc *ipu_crtc = data; > + struct drm_crtc *crtc = &ipu_crtc->base; > + > + list_del(&crtc->head); I don't think reaching into drm_crtc internals like this is going to be robust. Currently, this is either missing the rest of drm_crtc_cleanup, or it will crash if drm_crtc_init_with_planes hasn't been called yet. I think you could call devm_add_action with a function that calls drm_crtc_cleanup after drm_crtc_init_with_planes in ipu_crtc_init. Alternatively, the ipu_crtc allocation could be changed to kzalloc. It would then have to freed manually in the drm_crtc_funcs->destroy callback. regards Philipp ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel