[PATCH 1/2] drm/fbdev-helper: fail if driver provides no fbdev/fb probe functions

From: Marek Szyprowski
Date: Thu Oct 03 2024 - 05:29:27 EST


If caller doesn't provide driver->fbdev_probe nor funcs->fb_probe, then
fail early instead of causing potential NULL pointer dereference, because
fb_helper->fb won't be initialized in such case.

Fixes: 5d08c44e47b9 ("drm/fbdev: Add memory-agnostic fbdev client")
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index d5e8994345bb..fc260832326c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1635,6 +1635,9 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
ret = dev->driver->fbdev_probe(fb_helper, &sizes);
else if (fb_helper->funcs)
ret = fb_helper->funcs->fb_probe(fb_helper, &sizes);
+ else
+ ret = -ENODEV;
+
if (ret < 0)
return ret;

--
2.34.1