[PATCH] EDAC/versalnet: fix memory leak on device registration failure

[Guangshuo Li <lgs201920130244@gmail.com>]

init_one_mc() allocates dev with kzalloc() and registers it with
device_register(). If device_register() fails, the device has already
been initialized and holds its initial device reference.

The current error path eventually frees dev directly with kfree().
This bypasses the device release path and can leak driver-core
resources associated with the initialized device. The existing
versal_edac_release() callback is responsible for freeing dev once the
device reference reaches zero.

Call put_device() when device_register() fails so the initialized
device reference is dropped and versal_edac_release() performs the
proper cleanup. Return after freeing mci to avoid falling through to
the direct kfree() path, which remains necessary for failures that
occur before device_register() is called.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: d5fe2fec6c40 ("EDAC: Add a driver for the AMD Versal NET DDR controller")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/edac/versalnet_edac.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/versalnet_edac.c b/drivers/edac/versalnet_edac.c
index 3a06b41c1d84..db3bf5a1345b 100644
--- a/drivers/edac/versalnet_edac.c
+++ b/drivers/edac/versalnet_edac.c
@@ -829,8 +829,10 @@ static int init_one_mc(struct mc_priv *priv, struct platform_device *pdev, int i
 	dev->release = versal_edac_release;
 
 	rc = device_register(dev);
-	if (rc)
+	if (rc) {
+		put_device(dev);
 		goto err_mc_free;
+	}
 
 	mci->pdev = dev;
 	mc_init(mci, dev);
@@ -852,9 +854,9 @@ static int init_one_mc(struct mc_priv *priv, struct platform_device *pdev, int i
 	device_unregister(mci->pdev);
 err_mc_free:
 	edac_mc_free(mci);
+	return rc;
 err_dev_free:
 	kfree(dev);
-
 	return rc;
 }
 
-- 
2.43.0