From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D567C433EF for ; Mon, 13 Jun 2022 20:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351389AbiFMUzV (ORCPT ); Mon, 13 Jun 2022 16:55:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351370AbiFMUxa (ORCPT ); Mon, 13 Jun 2022 16:53:30 -0400 Received: from out0.migadu.com (out0.migadu.com [IPv6:2001:41d0:2:267::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CCE8C6C for ; Mon, 13 Jun 2022 13:16:33 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1655151391; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AqRJE5kHmUhU9DFMHo/l5MzOgI3EbkZf7j3BisUrZdo=; b=mIrxUO6yNmISFxVhORrnTzrHOpEeL/kLpMCN1K+a49yMcpUcxAigtTULezvJf30sL+wAyw Rp+NlTsOVqQfavGkK1yhonDcpWAej72Zl00+ifLviSvZ4cQgAtAzp1qpKRljb0D6kNe9Xl dJWXbiRA4Ni/5pltLo+AqeQNQWK+Duk= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Peter Collingbourne , Evgenii Stepanov , Florian Mayer , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH 11/32] kasan: introduce kasan_requires_meta Date: Mon, 13 Jun 2022 22:14:02 +0200 Message-Id: <4201bc563d9553bca0278124e5ee4f1fe9a84ba6.1655150842.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Konovalov Add a kasan_requires_meta() helper that indicates whether the enabled KASAN mode requires per-object metadata and use this helper in the common code. Also hide kasan_init_object_meta() under CONFIG_KASAN_GENERIC ifdef check, as Generic is the only mode that uses per-object metadata. To allow for a potential future change that makes Generic KASAN support the kasan.stacktrace command-line parameter, let kasan_requires_meta() return kasan_stack_collection_enabled() instead of simply returning true. Signed-off-by: Andrey Konovalov --- mm/kasan/common.c | 13 +++++-------- mm/kasan/kasan.h | 33 +++++++++++++++++++++++++++++---- mm/kasan/tags.c | 4 ---- 3 files changed, 34 insertions(+), 16 deletions(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 226eaa714da2..a3dee7cead89 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -88,13 +88,10 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) } #endif /* CONFIG_KASAN_STACK */ -/* - * Only allow cache merging when stack collection is disabled and no metadata - * is present. - */ +/* Only allow cache merging when no per-object metadata is present. */ slab_flags_t __kasan_never_merge(void) { - if (kasan_stack_collection_enabled()) + if (kasan_requires_meta()) return SLAB_KASAN; return 0; } @@ -151,7 +148,7 @@ void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, */ *flags |= SLAB_KASAN; - if (!kasan_stack_collection_enabled()) + if (!kasan_requires_meta()) return; ok_size = *size; @@ -219,7 +216,7 @@ void __kasan_cache_create_kmalloc(struct kmem_cache *cache) size_t __kasan_metadata_size(struct kmem_cache *cache) { - if (!kasan_stack_collection_enabled()) + if (!kasan_requires_meta()) return 0; return (cache->kasan_info.alloc_meta_offset ? sizeof(struct kasan_alloc_meta) : 0) + @@ -294,7 +291,7 @@ void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, const void *object) { /* Initialize per-object metadata if it is present. */ - if (kasan_stack_collection_enabled()) + if (kasan_requires_meta()) kasan_init_object_meta(cache, object); /* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */ diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index ff7a1597aa51..cf123d99f2fe 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -43,7 +43,7 @@ static inline bool kasan_sync_fault_possible(void) return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM; } -#else +#else /* CONFIG_KASAN_HW_TAGS */ static inline bool kasan_stack_collection_enabled(void) { @@ -60,7 +60,31 @@ static inline bool kasan_sync_fault_possible(void) return true; } -#endif +#endif /* CONFIG_KASAN_HW_TAGS */ + +#ifdef CONFIG_KASAN_GENERIC + +/* Generic KASAN uses per-object metadata to store stack traces. */ +static inline bool kasan_requires_meta(void) +{ + /* + * Technically, Generic KASAN always collects stack traces right now. + * However, let's use kasan_stack_collection_enabled() in case the + * kasan.stacktrace command-line argument is changed to affect + * Generic KASAN. + */ + return kasan_stack_collection_enabled(); +} + +#else /* CONFIG_KASAN_GENERIC */ + +/* Tag-based KASAN modes do not use per-object metadata. */ +static inline bool kasan_requires_meta(void) +{ + return false; +} + +#endif /* CONFIG_KASAN_GENERIC */ #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) @@ -271,13 +295,14 @@ void kasan_report_invalid_free(void *object, unsigned long ip); struct page *kasan_addr_to_page(const void *addr); struct slab *kasan_addr_to_slab(const void *addr); -void kasan_init_object_meta(struct kmem_cache *cache, const void *object); - #ifdef CONFIG_KASAN_GENERIC +void kasan_init_object_meta(struct kmem_cache *cache, const void *object); struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, const void *object); struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, const void *object); +#else +static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *object) { } #endif depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc); diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index f11c89505c77..4f24669085e9 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -17,10 +17,6 @@ #include "kasan.h" -void kasan_init_object_meta(struct kmem_cache *cache, const void *object) -{ -} - void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) { } -- 2.25.1