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authorNathan Chancellor <natechancellor@gmail.com>2019-05-31 22:30:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-06-01 15:51:31 -0700
commit0600597c854e53d2f9b7a6a718c1da2b8b4cb4db (patch)
treed0347c4729ef789899a6666113747037f74483bd
parentbb9f6f63f32da40ca34a921e377ad3181a4f9023 (diff)
download96b-common-0600597c854e53d2f9b7a6a718c1da2b8b4cb4db.tar.gz
kasan: initialize tag to 0xff in __kasan_kmalloc
When building with -Wuninitialized and CONFIG_KASAN_SW_TAGS unset, Clang warns: mm/kasan/common.c:484:40: warning: variable 'tag' is uninitialized when used here [-Wuninitialized] kasan_unpoison_shadow(set_tag(object, tag), size); ^~~ set_tag ignores tag in this configuration but clang doesn't realize it at this point in its pipeline, as it points to arch_kasan_set_tag as being the point where it is used, which will later be expanded to (void *)(object) without a use of tag. Initialize tag to 0xff, as it removes this warning and doesn't change the meaning of the code. Link: https://github.com/ClangBuiltLinux/linux/issues/465 Link: http://lkml.kernel.org/r/20190502163057.6603-1-natechancellor@gmail.com Fixes: 7f94ffbc4c6a ("kasan: add hooks implementation for tag-based mode") Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/kasan/common.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 36afcf64e016..242fdc01aaa9 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -464,7 +464,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
{
unsigned long redzone_start;
unsigned long redzone_end;
- u8 tag;
+ u8 tag = 0xff;
if (gfpflags_allow_blocking(flags))
quarantine_reduce();