cirrus_modeset_init() is initializing/registering the emulated fbdev
and, since commit c61b93fe51b1 ("drm/atomic: Fix remaining places where
!funcs->best_encoder is valid"), DRM internals can access/test some of
the fields in mode_config->funcs as part of the fbdev registration
process.
Make sure dev->mode_config.funcs is properly set to avoid dereferencing
a NULL pointer.
Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
Fixes: c61b93fe51b1 ("drm/atomic: Fix remaining places where
!funcs->best_encoder is valid")
---
Hi Dave,
As discussed on IRC, I'm sending this patch in a proper format. That's
probably better to wait for Eric's feeback before applying it though.
Regards,
Boris
---
drivers/gpu/drm/cirrus/cirrus_main.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/cirrus/cirrus_main.c
b/drivers/gpu/drm/cirrus/cirrus_main.c
index 80446e2d3ab6..76bcb43e7c06 100644
--- a/drivers/gpu/drm/cirrus/cirrus_main.c
+++ b/drivers/gpu/drm/cirrus/cirrus_main.c
@@ -185,14 +185,23 @@ int cirrus_driver_load(struct drm_device *dev, unsigned
long flags)
goto out;
}
+ /*
+ * cirrus_modeset_init() is initializing/registering the emulated fbdev
+ * and DRM internals can access/test some of the fields in
+ * mode_config->funcs as part of the fbdev registration process.
+ * Make sure dev->mode_config.funcs is properly set to avoid
+ * dereferencing a NULL pointer.
+ * FIXME: mode_config.funcs assignment should probably be done in
+ * cirrus_modeset_init() (that's a common pattern seen in other DRM
+ * drivers).
+ */
+ dev->mode_config.funcs = &cirrus_mode_funcs;
r = cirrus_modeset_init(cdev);
if (r) {
dev_err(&dev->pdev->dev, "Fatal error during modeset init:
%d\n", r);
goto out;
}
- dev->mode_config.funcs = (void *)&cirrus_mode_funcs;
-
return 0;
out:
cirrus_driver_unload(dev);
--
2.7.4
