[PATCH] mm/kfence: Null check is added for return value of addr_to_metadata

From: Manjeet Pawar
Date: Fri Sep 24 2021 - 09:55:54 EST


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@xxxxxxxxxxx>
---
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