[PATCH] mm/util.c: add a none zero check of "len"

[Pan Xinhui <xinhuix.pan@intel.com>]

Although this check should have been done by caller. But as it's exported to others,
It's better to add a none zero check of "len" like other functions.

Signed-off-by: xinhuix.pan <xinhuix.pan@intel.com>
---
  mm/util.c | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/mm/util.c b/mm/util.c
index fec39d4..3dc2873 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -72,6 +72,9 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp)
  {
  	void *p;
  
+	if (unlikely(!len))
+		return ERR_PTR(-EINVAL);
+
  	p = kmalloc_track_caller(len, gfp);
  	if (p)
  		memcpy(p, src, len);
@@ -91,6 +94,8 @@ void *memdup_user(const void __user *src, size_t len)
  {
  	void *p;
  
+	if (unlikely(!len))
+		return ERR_PTR(-EINVAL);
  	/*
  	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
  	 * cause pagefault, which makes it pointless to use GFP_NOFS
-- 
1.9.1

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