[PATCH v2] EDAC/altera: Fix SDMMC PortB OF node reference leak

[Yuho Choi]

of_find_compatible_node() returns a device node with its refcount
incremented. altr_portb_setup() looks up the SDMMC ECC node but does
not drop that reference on error paths or after successful setup.

Route those exits through an of_node_put() cleanup path. Also free the
EDAC control info if devres_open_group() fails after dci has been
allocated, and release the devres group before freeing dci because
altdev is stored in dci->pvt_info.

Fixes: 911049845d70 ("EDAC, altera: Add Arria10 SD-MMC EDAC support")
Signed-off-by: Yuho Choi <dbgh9129@xxxxxxxxx>
---
Changes since v1:
- Free the EDAC control info when devres_open_group() fails after dci
  has been allocated.
- Release the PortB devres group before freeing dci so altdev->ddev
  remains valid during devres cleanup.
- Keep the !dci failure path limited to dropping the OF node reference.

 drivers/edac/altera_edac.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index 4edd2088c2db..1b050e35ec4b 100644
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -1526,15 +1526,18 @@ static int altr_portb_setup(struct altr_edac_device_dev *device)
 		edac_printk(KERN_ERR, EDAC_DEVICE,
 			    "%s: Unable to allocate PortB EDAC device\n",
 			    ecc_name);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto out_put_node;
 	}
 
 	/* Initialize the PortB EDAC device structure from PortA structure */
 	altdev = dci->pvt_info;
 	*altdev = *device;
 
-	if (!devres_open_group(&altdev->ddev, altr_portb_setup, GFP_KERNEL))
-		return -ENOMEM;
+	if (!devres_open_group(&altdev->ddev, altr_portb_setup, GFP_KERNEL)) {
+		rc = -ENOMEM;
+		goto err_free_ctl;
+	}
 
 	/* Update PortB specific values */
 	altdev->edac_dev_name = ecc_name;
@@ -1607,13 +1610,17 @@ static int altr_portb_setup(struct altr_edac_device_dev *device)
 
 	devres_remove_group(&altdev->ddev, altr_portb_setup);
 
-	return 0;
+	rc = 0;
+	goto out_put_node;
 
 err_release_group_1:
-	edac_device_free_ctl_info(dci);
 	devres_release_group(&altdev->ddev, altr_portb_setup);
+err_free_ctl:
+	edac_device_free_ctl_info(dci);
 	edac_printk(KERN_ERR, EDAC_DEVICE,
 		    "%s:Error setting up EDAC device: %d\n", ecc_name, rc);
+out_put_node:
+	of_node_put(np);
 	return rc;
 }
 
-- 
2.43.0