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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1662412021; 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=snUut4Q4q+dUymH54JVYowFIFl//oD93Q0T08XoiwNc=; b=tshzPPvnQJLzzS7rwtoPtEPCQmUW4py+AZlb3mgTV1F/1j6iB84itWf3biY55HquprhixV w4BJsWEjGjpLLnzha+w5oKZObQkbUANuZuHQM1VU1CStGEZtw1q1i2c9AS+dXvlj4FHuq9 yNPWCH9YMVz7QHhA7wQ/8OJwE7Qp4V0= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Peter Collingbourne , Evgenii Stepanov , Florian Mayer , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH mm v3 11/34] kasan: introduce kasan_requires_meta Date: Mon, 5 Sep 2022 23:05:26 +0200 Message-Id: In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tshzPPvn; spf=pass (imf25.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662412022; a=rsa-sha256; cv=none; b=1nx/LNEYk5hhF0bDhI4FgKY7xXNjCZPQqIDciKx1LfPSF936eB4CR31pi28oKraQ/CB2oG 1Xif2M9S8jZG3m3ifWX5z+Ig0d/9nJqj1E5OJHok99T51nFcsjdEumWrjONuoq1aGoYKHZ 4JjuQTcfTQH7N1WeylZFJWR5o2jgLaY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662412022; 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=snUut4Q4q+dUymH54JVYowFIFl//oD93Q0T08XoiwNc=; b=KktfCZ7UITQLvHk2BzawBCxXGlbqlaIDKNfBaWyWWBzIV0k30Qa2EI8HiGo7sSXCTsEcEo q7K+fnM4/O3aBEZUIVc8eVdzkeDbIC4LPQOJUNzDNHmEd5FPPvf5b/xjTbaLS0t0yjQDQ2 Gk65FQ2M5YTJ/nTGJKTrMgwRmnsZOug= Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=tshzPPvn; spf=pass (imf25.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Stat-Signature: sutra78jbo1uys51m3ma3mjhu4kbwtek X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 5B16DA007F X-HE-Tag: 1662412022-473661 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. Reviewed-by: Marco Elver 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 19ddc0ed0e7b..d0300954d76b 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; } @@ -152,7 +149,7 @@ 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; @@ -220,7 +217,7 @@ 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) + @@ -295,7 +292,7 @@ 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) { }