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From:   Manjeet Pawar <manjeet.p@samsung.com>
To:     glider@google.com, elver@google.com, dvyukov@google.com,
        akpm@linux-foundation.org, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     r.thapliyal@samsung.com, a.sahrawat@samsung.com,
        v.narang@samsung.com, Manjeet Pawar <manjeet.p@samsung.com>
Subject: [PATCH] mm/kfence: Null check is added for return value of
 addr_to_metadata
Date:   Fri, 24 Sep 2021 17:44:02 +0530
Message-Id: <1632485642-20625-1-git-send-email-manjeet.p@samsung.com>
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 105P
References: <CGME20210924121457epcas5p39266266f9cef79177f2301a6a4f7d79a@epcas5p3.samsung.com>
Precedence: bulk

This patch add null check for return value of addr_to_metadata().
currently 'meta' is geting accessed without any NULL check but it is
usually checked for this function.

Signed-off-by: Manjeet Pawar <manjeet.p@samsung.com>
---
 mm/kfence/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 575c685aa642..9b953cfa7fee 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -802,6 +802,9 @@ void __kfence_free(void *addr)
 {
 	struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
 
+	if (unlikely(!meta))
+		return;
+
 	/*
 	 * If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing
 	 * the object, as the object page may be recycled for other-typed
-- 
2.17.1