[v3,21/71] drm/vc4: crtc: Switch to drmm_kzalloc

Commit Message

Maxime Ripard June 29, 2022, 12:34 p.m. UTC

Our internal structure that stores the DRM entities structure is allocated
through a device-managed kzalloc.

This means that this will eventually be freed whenever the device is
removed. In our case, the most likely source of removal is that the main
device is going to be unbound, and component_unbind_all() is being run.

However, it occurs while the DRM device is still registered, which will
create dangling pointers, eventually resulting in use-after-free.

Switch to a DRM-managed allocation to keep our structure until the DRM
driver doesn't need it anymore.

Reviewed-by: Dave Stevenson <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
---
 drivers/gpu/drm/vc4/vc4_crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index bcce61879d53..d5158a6c0f21 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -1284,7 +1284,7 @@  static int vc4_crtc_bind(struct device *dev, struct device *master, void *data)
 	struct drm_crtc *crtc;
 	int ret;
 
-	vc4_crtc = devm_kzalloc(dev, sizeof(*vc4_crtc), GFP_KERNEL);
+	vc4_crtc = drmm_kzalloc(drm, sizeof(*vc4_crtc), GFP_KERNEL);
 	if (!vc4_crtc)
 		return -ENOMEM;
 	crtc = &vc4_crtc->base;