From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: [PATCH] kasan: Fix tag for large allocations when using CONFIG_SLAB
Date: Fri, 1 Oct 2021 03:41:05 +0100 [thread overview]
Message-ID: <20211001024105.3217339-1-willy@infradead.org> (raw)
If an object is allocated on a tail page of a multi-page slab, kasan
will get the wrong tag because page->s_mem is NULL for tail pages.
I'm not quite sure what the user-visible effect of this might be.
Fixes: 7f94ffbc4c6a ("kasan: add hooks implementation for tag-based mode")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/kasan/common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 2baf121fb8c5..41779ad109cd 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -298,7 +298,7 @@ static inline u8 assign_tag(struct kmem_cache *cache,
/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
#ifdef CONFIG_SLAB
/* For SLAB assign tags based on the object index in the freelist. */
- return (u8)obj_to_index(cache, virt_to_page(object), (void *)object);
+ return (u8)obj_to_index(cache, virt_to_head_page(object), (void *)object);
#else
/*
* For SLUB assign a random tag during slab creation, otherwise reuse
--
2.32.0
next reply other threads:[~2021-10-01 2:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 2:41 Matthew Wilcox (Oracle) [this message]
2021-10-01 10:30 ` Marco Elver
2021-10-01 13:29 ` Andrey Konovalov
2021-10-01 14:05 ` Matthew Wilcox
2021-10-03 16:27 ` Andrey Konovalov
2021-10-03 16:27 ` Andrey Konovalov
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