linux-kernel - [PATCH][next] drivers: base: swnode: check if swnode is null before dereferencing it

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Message-Id: <20181222124333.13561-1-colin.king@canonical.com>
Date:   Sat, 22 Dec 2018 12:43:33 +0000
From:   Colin King <colin.king@...onical.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] drivers: base: swnode: check if swnode is null before dereferencing it

From: Colin Ian King <colin.king@...onical.com>

The macro to_software_mode can potentially return NULL, so also add
a null check on the swnode before dereferencing it to avoid any null
pointer dereferences.

Detected by CoverityScan, CID#1476052 ("Explicit null dereferenced")

Fixes: 59abd83672f7 ("drivers: base: Introducing software nodes to the firmware node framework")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/base/swnode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 306bb93287af..204aa7d049e0 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -477,7 +477,8 @@ software_node_get_parent(const struct fwnode_handle *fwnode)
 {
 	struct software_node *swnode = to_software_node(fwnode);
 
-	return swnode->parent ? &swnode->parent->fwnode : NULL;
+	return swnode ? (swnode->parent ? &swnode->parent->fwnode : NULL) :
+			NULL;
 }
 
 struct fwnode_handle *
-- 
2.19.1