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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1658189487; 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=rlDhQ93GQxymrct+XncFBhhuVBx6ex2JMh1zy3E0kDY=; b=Dgr8rg8WoNZbfG4qteMwCiuXSs7DjvjVLmtmSAN9DkiwslqKe1B9fXH6DAP6qn1kZLFG02 oaWNyPv+1uNDXVnqvO5BjoO9rRjlA9YLc+pmbRgiM2CbG5OE4fEqaZJXdXaCqtZP82UKv2 dLTO1JEP5QDrDeSLu5qXidUqDfEM9SM= 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 mm v2 11/33] kasan: introduce kasan_requires_meta Date: Tue, 19 Jul 2022 02:09:51 +0200 Message-Id: <54b97ba71189b557b4b70e9cdcc821ca4349abfb.1658189199.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Dgr8rg8W; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf07.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658189488; a=rsa-sha256; cv=none; b=2+tQEx2KkCko11bJMqd21PPpdN/5qAII3e/Tsel/P+WqgWV08mkL5OXmpXZgEnPSuazFwZ S3w/U/zrCvRxnA2cep9/IEhg5Z4uwV6/Ca4otfhTumw9B+R3T4JkkCn8JcDk2b5xE3fB6d QzystulUFQchP9rH5o50cxwWwVmBzkg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658189488; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rlDhQ93GQxymrct+XncFBhhuVBx6ex2JMh1zy3E0kDY=; b=xmd+6/6U23pZuAuG5B/bMYp4Xhls9RR5iDiVys1YW9iYxDLhgQ2H2FTkb9XQ6wvRZH9vHI j9ZZe9OFVVkduOlfd+uvZQDvik+YomZZW70vci9z5PrcnirwSEgnmSZsLzSi1Nkb7D8dES 8lvxtpsASSqpE2ocyIVfOr4kdpDQInA= X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 07F514005E Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Dgr8rg8W; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf07.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev X-Stat-Signature: dddbzdiwokdj56666wz1o6tkzjsy9pmo X-HE-Tag: 1658189487-474039 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 d46bb2b351ff..d2ec4e6af675 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 fdd577f3eb9d..1736abd661b6 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) @@ -272,13 +296,14 @@ void kasan_report_invalid_free(void *object, unsigned long ip, enum kasan_report 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) { }