linux-kernel - [PATCH v2] kobject: Restore old behaviour of kobject

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Message-Id: <20200803082706.65347-1-andriy.shevchenko@linux.intel.com>
Date:   Mon,  3 Aug 2020 11:27:06 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Qu Wenruo <quwenruo.btrfs@....com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Subject: [PATCH v2] kobject: Restore old behaviour of kobject_del(NULL)

The commit 079ad2fb4bf9 ("kobject: Avoid premature parent object freeing in
kobject_cleanup()") inadvertently dropped a possibility to call kobject_del()
with NULL pointer. Restore the old behaviour.

Fixes: 079ad2fb4bf9 ("kobject: Avoid premature parent object freeing in kobject_cleanup()")
Reported-by: Qu Wenruo <quwenruo.btrfs@....com>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
v2: replaced ?: with plain conditional (Greg)
 lib/kobject.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/kobject.c b/lib/kobject.c
index 3afb939f2a1c..9dce68c378e6 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -637,8 +637,12 @@ static void __kobject_del(struct kobject *kobj)
  */
 void kobject_del(struct kobject *kobj)
 {
-	struct kobject *parent = kobj->parent;
+	struct kobject *parent;
+
+	if (!kobj)
+		return;
 
+	parent = kobj->parent;
 	__kobject_del(kobj);
 	kobject_put(parent);
 }
-- 
2.27.0