kasan, slab: make freelist stored without tags (51dedad0) · Commits · 戴 / test

Similarly to "kasan, slub: move kasan_poison_slab hook before page_address", move kasan_poison_slab() before alloc_slabmgmt(), which calls page_address(), to make page_address() return value to be non-tagged. This, combined with calling kasan_reset_tag() for off-slab slab management object, leads to freelist being stored non-tagged. Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@google.com Signed-off-by:

Andrey Konovalov <andreyknvl@google.com> Tested-by:

Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/slab.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -2359,7 +2359,7 @@ static void alloc_slabmgmt(struct kmem_cache cachep,
		void *freelist;
		void *addr = page_address(page);

		page->s_mem = kasan_reset_tag(addr) + colour_off;
		page->s_mem = addr + colour_off;
		page->active = 0;

		if (OBJFREELIST_SLAB(cachep))
		@@ -2368,6 +2368,7 @@ static void alloc_slabmgmt(struct kmem_cache cachep,
		/* Slab management obj is off-slab. */
		freelist = kmem_cache_alloc_node(cachep->freelist_cache,
		local_flags, nodeid);
		freelist = kasan_reset_tag(freelist);
		if (!freelist)
		return NULL;
		} else {
		@@ -2681,6 +2682,13 @@ static struct page cache_grow_begin(struct kmem_cache cachep,

		offset *= cachep->colour_off;

		/*
		* Call kasan_poison_slab() before calling alloc_slabmgmt(), so
		* page_address() in the latter returns a non-tagged pointer,
		* as it should be for slab pages.
		*/
		kasan_poison_slab(page);

		/* Get slab management. */
		freelist = alloc_slabmgmt(cachep, page, offset,
		local_flags & ~GFP_CONSTRAINT_MASK, page_node);
		@@ -2689,7 +2697,6 @@ static struct page cache_grow_begin(struct kmem_cache cachep,

		slab_map_pages(cachep, page, freelist);

		kasan_poison_slab(page);
		cache_init_objs(cachep, page);

		if (gfpflags_allow_blocking(local_flags))

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