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mm: ksize() should silently accept a NULL pointer

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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>
This commit is contained in:
William Kucharski 2020-08-06 23:18:17 -07:00 committed by Linus Torvalds
parent 453431a549
commit fa9ba3aa89
1 changed files with 5 additions and 9 deletions
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14
mm/slab_common.c
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@ -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);