From da844b787245194cfd69f0f1d2fb1dd3640a8a6d Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 29 Apr 2021 23:00:06 -0700 Subject: kasan, mm: integrate slab init_on_alloc with HW_TAGS This change uses the previously added memory initialization feature of HW_TAGS KASAN routines for slab memory when init_on_alloc is enabled. With this change, memory initialization memset() is no longer called when both HW_TAGS KASAN and init_on_alloc are enabled. Instead, memory is initialized in KASAN runtime. The memory initialization memset() is moved into slab_post_alloc_hook() that currently directly follows the initialization loop. A new argument is added to slab_post_alloc_hook() that indicates whether to initialize the memory or not. To avoid discrepancies with which memory gets initialized that can be caused by future changes, both KASAN hook and initialization memset() are put together and a warning comment is added. Combining setting allocation tags with memory initialization improves HW_TAGS KASAN performance when init_on_alloc is enabled. Link: https://lkml.kernel.org/r/c1292aeb5d519da221ec74a0684a949b027d7720.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Branislav Rankov Cc: Catalin Marinas Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Joonsoo Kim Cc: Kevin Brodsky Cc: Pekka Enberg Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slub.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) (limited to 'mm/slub.c') diff --git a/mm/slub.c b/mm/slub.c index a178c738fc92..5cf35250f20c 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2823,6 +2823,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, struct page *page; unsigned long tid; struct obj_cgroup *objcg = NULL; + bool init = false; s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags); if (!s) @@ -2900,12 +2901,10 @@ redo: } maybe_wipe_obj_freeptr(s, object); - - if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) - memset(kasan_reset_tag(object), 0, s->object_size); + init = slab_want_init_on_alloc(gfpflags, s); out: - slab_post_alloc_hook(s, objcg, gfpflags, 1, &object); + slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init); return object; } @@ -3357,20 +3356,16 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, c->tid = next_tid(c->tid); local_irq_enable(); - /* Clear memory outside IRQ disabled fastpath loop */ - if (unlikely(slab_want_init_on_alloc(flags, s))) { - int j; - - for (j = 0; j < i; j++) - memset(kasan_reset_tag(p[j]), 0, s->object_size); - } - - /* memcg and kmem_cache debug support */ - slab_post_alloc_hook(s, objcg, flags, size, p); + /* + * memcg and kmem_cache debug support and memory initialization. + * Done outside of the IRQ disabled fastpath loop. + */ + slab_post_alloc_hook(s, objcg, flags, size, p, + slab_want_init_on_alloc(flags, s)); return i; error: local_irq_enable(); - slab_post_alloc_hook(s, objcg, flags, i, p); + slab_post_alloc_hook(s, objcg, flags, i, p, false); __kmem_cache_free_bulk(s, i, p); return 0; } @@ -3580,7 +3575,7 @@ static void early_kmem_cache_node_alloc(int node) init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); init_tracking(kmem_cache_node, n); #endif - n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL); + n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false); page->freelist = get_freepointer(kmem_cache_node, n); page->inuse = 1; page->frozen = 0; -- cgit v1.2.3