linux-kernel - [PATCH] mm/kfence: Null check is added for return value of addr_to

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Date:   Fri, 24 Sep 2021 17:44:02 +0530
From:   Manjeet Pawar <manjeet.p@...sung.com>
To:     glider@...gle.com, elver@...gle.com, dvyukov@...gle.com,
        akpm@...ux-foundation.org, kasan-dev@...glegroups.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     r.thapliyal@...sung.com, a.sahrawat@...sung.com,
        v.narang@...sung.com, Manjeet Pawar <manjeet.p@...sung.com>
Subject: [PATCH] mm/kfence: Null check is added for return value of
 addr_to_metadata

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@...sung.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