linux-kernel - [RFC PATCH 1/5] livepatch: Fix kobject memleak

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Message-Id: <20190502023142.20139-2-tobin@kernel.org>
Date:   Thu,  2 May 2019 12:31:38 +1000
From:   "Tobin C. Harding" <tobin@...nel.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>,
        Jiri Kosina <jikos@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Petr Mladek <pmladek@...e.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "Tobin C. Harding" <tobin@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Joe Lawrence <joe.lawrence@...hat.com>,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 1/5] livepatch: Fix kobject memleak

Currently error return from kobject_init_and_add() is not followed by a
call to kobject_put().  This means there is a memory leak.

Add call to kobject_put() in error path of kobject_init_and_add().

Signed-off-by: Tobin C. Harding <tobin@...nel.org>
---
 kernel/livepatch/core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index eb0ee10a1981..98295de2172b 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -727,7 +727,9 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 	ret = kobject_init_and_add(&func->kobj, &klp_ktype_func,
 				   &obj->kobj, "%s,%lu", func->old_name,
 				   func->old_sympos ? func->old_sympos : 1);
-	if (!ret)
+	if (ret)
+		kobject_put(&func->kobj);
+	else
 		func->kobj_added = true;
 
 	return ret;
@@ -803,8 +805,10 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
 	name = klp_is_module(obj) ? obj->name : "vmlinux";
 	ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object,
 				   &patch->kobj, "%s", name);
-	if (ret)
+	if (ret) {
+		kobject_put(&obj->kobj);
 		return ret;
+	}
 	obj->kobj_added = true;
 
 	klp_for_each_func(obj, func) {
@@ -862,8 +866,10 @@ static int klp_init_patch(struct klp_patch *patch)
 
 	ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch,
 				   klp_root_kobj, "%s", patch->mod->name);
-	if (ret)
+	if (ret) {
+		kobject_put(&patch->kobj);
 		return ret;
+	}
 	patch->kobj_added = true;
 
 	if (patch->replace) {
-- 
2.21.0