On 12/3/21 14:15, Carsten Haitzler wrote:
On 12/3/21 10:09, Liviu Dudau wrote:
If drm_universal_plane_init() fails early we jump to the common cleanup code that calls komeda_plane_destroy() which in turn could access the uninitalised drm_plane and crash. Return early if an error is detected without going through
the common code.

Reported-by: Steven Price <steven.pr...@arm.com>
Signed-off-by: Liviu Dudau <liviu.du...@arm.com>
---
  drivers/gpu/drm/arm/display/komeda/komeda_plane.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
index aa193c58f4bf6d9..517b94c3bcaf966 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
@@ -279,8 +279,10 @@ static int komeda_plane_add(struct komeda_kms_dev *kms,
      komeda_put_fourcc_list(formats);
-    if (err)
-        goto cleanup;
+    if (err) {
+        kfree(kplane);
+        return err;
+    }
      drm_plane_helper_add(plane, &komeda_plane_helper_funcs);


Ummm... can I disagree here? this goto cleanup I think is just fine because plane has been set before drm_universal_plane_init() is called which is before the if (err) here. komeda_plane_destroy() in cleanup: does all the right things, so this patch isn't needed. I think it's less clean as it adds a new "handle error" path special-case instance where a special case is not needed. The fix to Zhou's original patch was needed for exactly the reason Liviu said - but not this one... ?

Let me take that back - it seems an init fail shouldn't call cleanup but the init fail doesn't quite cleanup properly. Steven found this and already sent a patch.

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