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authorWilliam Kucharski <william.kucharski@oracle.com>2020-08-06 23:18:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:22 -0700
commitfa9ba3aa89f9f1c003b5f5cde893bbbc140c7223 (patch)
treed099883fd711d6af50a06e5a60c0656fc7bdaae9
parent453431a54934d917153c65211b2dabf45562ca88 (diff)
downloadlinux-fa9ba3aa89f9f1c003b5f5cde893bbbc140c7223.tar.bz2
mm: ksize() should silently accept a NULL pointer
Other mm routines such as kfree() and kzfree() silently do the right thing if passed a NULL pointer, so ksize() should do the same. Signed-off-by: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/20200616225409.4670-1-william.kucharski@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/slab_common.c14
1 files changed, 5 insertions, 9 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index f47a097bb4b8..e493203b5002 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1681,10 +1681,9 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size,
gfp_t flags)
{
void *ret;
- size_t ks = 0;
+ size_t ks;
- if (p)
- ks = ksize(p);
+ ks = ksize(p);
if (ks >= new_size) {
p = kasan_krealloc((void *)p, new_size, flags);
@@ -1744,10 +1743,9 @@ void kfree_sensitive(const void *p)
size_t ks;
void *mem = (void *)p;
- if (unlikely(ZERO_OR_NULL_PTR(mem)))
- return;
ks = ksize(mem);
- memzero_explicit(mem, ks);
+ if (ks)
+ memzero_explicit(mem, ks);
kfree(mem);
}
EXPORT_SYMBOL(kfree_sensitive);
@@ -1770,8 +1768,6 @@ size_t ksize(const void *objp)
{
size_t size;
- if (WARN_ON_ONCE(!objp))
- return 0;
/*
* We need to check that the pointed to object is valid, and only then
* unpoison the shadow memory below. We use __kasan_check_read(), to
@@ -1785,7 +1781,7 @@ size_t ksize(const void *objp)
* We want to perform the check before __ksize(), to avoid potentially
* crashing in __ksize() due to accessing invalid metadata.
*/
- if (unlikely(objp == ZERO_SIZE_PTR) || !__kasan_check_read(objp, 1))
+ if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
return 0;
size = __ksize(objp);