kasan: use unchecked __memset internally

KASAN code is supposed to use the unchecked __memset implementation when
accessing its metadata.

Change uses of memset to __memset in mm/kasan/.

Link: https://lkml.kernel.org/r/6f621966c6f52241b5aaa7220c348be90c075371.1696605143.git.andreyknvl@google.com
Fixes: 59e6e098 ("kasan: introduce kasan_complete_mode_report_info")
Fixes: 3c5c3cfb ("kasan: support backing vmalloc space with real shadow memory")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/kasan/report.c

@@ -538,7 +538,7 @@ void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_ty
 
 	start_report(&flags, true);
 
-	memset(&info, 0, sizeof(info));
+	__memset(&info, 0, sizeof(info));
 	info.type = type;
 	info.access_addr = ptr;
 	info.access_size = 0;
@@ -576,7 +576,7 @@ bool kasan_report(const void *addr, size_t size, bool is_write,
 
 	start_report(&irq_flags, true);
 
-	memset(&info, 0, sizeof(info));
+	__memset(&info, 0, sizeof(info));
 	info.type = KASAN_REPORT_ACCESS;
 	info.access_addr = addr;
 	info.access_size = size;

mm/kasan/shadow.c

@@ -324,7 +324,7 @@ static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
 	if (!page)
 		return -ENOMEM;
 
-	memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
+	__memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
 	pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
 
 	spin_lock(&init_mm.page_table_lock);