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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88999C468BC for ; Mon, 10 Jun 2019 07:28:30 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5FE7620859 for ; Mon, 10 Jun 2019 07:28:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="GGZH+n2/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FE7620859 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NYNGtLXc1+uVIK9xhvsOeiqWAGccs5Y9HNomKNHibSQ=; b=GGZH+n2/yVZo7T zJCT2RKGTHbHL43B/brZa5fqNZYaZ2tKDPY1h0iKWaYFIWXOZiz7l2PWGn09TlK1X6lwhstHgvUA6 4f/2cMhSYTNNaw0Q3zu4HKKIS3xO7ONZ2JLiPZZw/nhVTkG7xbHotneFGKsml/SDJi2ay7SqaGql8 OgzdjlRlVqdwpLMEEYGG5AV0TSL85r08yBJKq/ngX4Mj/HU14blnUzRiSeFKygBgmZoJWgwclBO2R mvZRN4ibIM9f1VcPMMrmoDdnSIpGhefGMHoD9vCmzA8V8CrxdHQVJD2sXZ+k7gHw7KctrkYeWN4qG Pc37Gt5cTvdaHv9b39Mg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haEjF-0002uw-KS; Mon, 10 Jun 2019 07:28:29 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1haEjA-0002tC-CE; Mon, 10 Jun 2019 07:28:27 +0000 X-UUID: 098f36fa672042ebb0cf6385f8cd4eae-20190609 X-UUID: 098f36fa672042ebb0cf6385f8cd4eae-20190609 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 1595202878; Sun, 09 Jun 2019 23:28:14 -0800 Received: from mtkmbs07n1.mediatek.inc (172.21.101.16) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Mon, 10 Jun 2019 00:28:12 -0700 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Mon, 10 Jun 2019 15:28:11 +0800 Received: from [172.21.84.99] (172.21.84.99) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Mon, 10 Jun 2019 15:28:10 +0800 Message-ID: <1560151690.20384.3.camel@mtksdccf07> Subject: Re: [PATCH v2] kasan: add memory corruption identification for software tag-based mode From: Walter Wu To: Dmitry Vyukov Date: Mon, 10 Jun 2019 15:28:10 +0800 In-Reply-To: References: <1559651172-28989-1-git-send-email-walter-zh.wu@mediatek.com> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190610_002824_432318_7C633944 X-CRM114-Status: GOOD ( 31.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wsd_upstream , "Jason A. Donenfeld" , Vasily Gorbik , Arnd Bergmann , Linux-MM , Andrey Konovalov , "linux-mediatek@lists.infradead.org" , LKML , kasan-dev , Pekka Enberg , Martin Schwidefsky , Miles Chen =?UTF-8?Q?=28=E9=99=B3=E6=B0=91=E6=A8=BA=29?= , Alexander Potapenko , David Rientjes , Matthias Brugger , Andrey Ryabinin , Christoph Lameter , Joonsoo Kim , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 2019-06-07 at 21:18 +0800, Dmitry Vyukov wrote: > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > > index b40ea104dd36..be0667225b58 100644 > > --- a/include/linux/kasan.h > > +++ b/include/linux/kasan.h > > @@ -164,7 +164,11 @@ void kasan_cache_shutdown(struct kmem_cache *cache); > > > > #else /* CONFIG_KASAN_GENERIC */ > > > > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > > +void kasan_cache_shrink(struct kmem_cache *cache); > > +#else > > Please restructure the code so that we don't duplicate this function > name 3 times in this header. > We have fixed it, Thank you for your reminder. > > static inline void kasan_cache_shrink(struct kmem_cache *cache) {} > > +#endif > > static inline void kasan_cache_shutdown(struct kmem_cache *cache) {} > > > > #endif /* CONFIG_KASAN_GENERIC */ > > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan > > index 9950b660e62d..17a4952c5eee 100644 > > --- a/lib/Kconfig.kasan > > +++ b/lib/Kconfig.kasan > > @@ -134,6 +134,15 @@ config KASAN_S390_4_LEVEL_PAGING > > to 3TB of RAM with KASan enabled). This options allows to force > > 4-level paging instead. > > > > +config KASAN_SW_TAGS_IDENTIFY > > + bool "Enable memory corruption idenitfication" > > s/idenitfication/identification/ > I should replace my glasses. > > + depends on KASAN_SW_TAGS > > + help > > + Now tag-based KASAN bug report always shows invalid-access error, This > > + options can identify it whether it is use-after-free or out-of-bound. > > + This will make it easier for programmers to see the memory corruption > > + problem. > > This description looks like a change description, i.e. it describes > the current behavior and how it changes. I think code comments should > not have such, they should describe the current state of the things. > It should also mention the trade-off, otherwise it raises reasonable > questions like "why it's not enabled by default?" and "why do I ever > want to not enable it?". > I would do something like: > > This option enables best-effort identification of bug type > (use-after-free or out-of-bounds) > at the cost of increased memory consumption for object quarantine. > I totally agree with your comments. Would you think we should try to add the cost? It may be that it consumes about 1/128th of available memory at full quarantine usage rate. > > > > > + > > config TEST_KASAN > > tristate "Module for testing KASAN for bug detection" > > depends on m && KASAN > > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > > index 5d1065efbd47..d8540e5070cb 100644 > > --- a/mm/kasan/Makefile > > +++ b/mm/kasan/Makefile > > @@ -19,3 +19,4 @@ CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > obj-$(CONFIG_KASAN) := common.o init.o report.o > > obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o > > obj-$(CONFIG_KASAN_SW_TAGS) += tags.o tags_report.o > > +obj-$(CONFIG_KASAN_SW_TAGS_IDENTIFY) += quarantine.o > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index 80bbe62b16cd..e309fbbee831 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -81,7 +81,7 @@ static inline depot_stack_handle_t save_stack(gfp_t flags) > > return depot_save_stack(&trace, flags); > > } > > > > -static inline void set_track(struct kasan_track *track, gfp_t flags) > > +void set_track(struct kasan_track *track, gfp_t flags) > > If you make it non-static, it should get kasan_ prefix. The name is too generic. > Ok, We will add it into next version. > > > { > > track->pid = current->pid; > > track->stack = save_stack(flags); > > @@ -457,7 +457,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > > return false; > > > > set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT); > > - quarantine_put(get_free_info(cache, object), cache); > > + quarantine_put(get_free_info(cache, tagged_object), cache); > > > > return IS_ENABLED(CONFIG_KASAN_GENERIC); > > } > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > > index 3e0c11f7d7a1..1be04abe2e0d 100644 > > --- a/mm/kasan/kasan.h > > +++ b/mm/kasan/kasan.h > > @@ -98,6 +98,12 @@ struct kasan_alloc_meta { > > struct qlist_node { > > struct qlist_node *next; > > }; > > +struct qlist_object { > > + unsigned long addr; > > + unsigned int size; > > + struct kasan_track free_track; > > + struct qlist_node qnode; > > +}; > > struct kasan_free_meta { > > /* This field is used while the object is in the quarantine. > > * Otherwise it might be used for the allocator freelist. > > @@ -133,11 +139,12 @@ void kasan_report(unsigned long addr, size_t size, > > bool is_write, unsigned long ip); > > void kasan_report_invalid_free(void *object, unsigned long ip); > > > > -#if defined(CONFIG_KASAN_GENERIC) && \ > > - (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > > +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS_IDENTIFY)) \ > > + && (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) > > void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache); > > void quarantine_reduce(void); > > void quarantine_remove_cache(struct kmem_cache *cache); > > +void set_track(struct kasan_track *track, gfp_t flags); > > #else > > static inline void quarantine_put(struct kasan_free_meta *info, > > struct kmem_cache *cache) { } > > @@ -151,6 +158,31 @@ void print_tags(u8 addr_tag, const void *addr); > > > > u8 random_tag(void); > > > > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > > +bool quarantine_find_object(void *object, > > + struct kasan_track *free_track); > > + > > +struct qlist_object *qobject_create(struct kasan_free_meta *info, > > + struct kmem_cache *cache); > > + > > +void qobject_free(struct qlist_node *qlink, struct kmem_cache *cache); > > +#else > > +static inline bool quarantine_find_object(void *object, > > + struct kasan_track *free_track) > > +{ > > + return false; > > +} > > + > > +static inline struct qlist_object *qobject_create(struct kasan_free_meta *info, > > + struct kmem_cache *cache) > > +{ > > + return NULL; > > +} > > + > > +static inline void qobject_free(struct qlist_node *qlink, > > + struct kmem_cache *cache) {} > > +#endif > > + > > #else > > > > static inline void print_tags(u8 addr_tag, const void *addr) { } > > @@ -160,6 +192,20 @@ static inline u8 random_tag(void) > > return 0; > > } > > > > +static inline bool quarantine_find_object(void *object, > > > Please restructure the code so that we don't duplicate this function > name 3 times in this header. > We have fixed it. > > + struct kasan_track *free_track) > > +{ > > + return false; > > +} > > + > > +static inline struct qlist_object *qobject_create(struct kasan_free_meta *info, > > + struct kmem_cache *cache) > > +{ > > + return NULL; > > +} > > + > > +static inline void qobject_free(struct qlist_node *qlink, > > + struct kmem_cache *cache) {} > > #endif > > > > #ifndef arch_kasan_set_tag > > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > > index 978bc4a3eb51..43b009659d80 100644 > > --- a/mm/kasan/quarantine.c > > +++ b/mm/kasan/quarantine.c > > @@ -61,12 +61,16 @@ static void qlist_init(struct qlist_head *q) > > static void qlist_put(struct qlist_head *q, struct qlist_node *qlink, > > size_t size) > > { > > - if (unlikely(qlist_empty(q))) > > + struct qlist_node *prev_qlink = q->head; > > + > > + if (unlikely(qlist_empty(q))) { > > q->head = qlink; > > - else > > - q->tail->next = qlink; > > - q->tail = qlink; > > - qlink->next = NULL; > > + q->tail = qlink; > > + qlink->next = NULL; > > + } else { > > + q->head = qlink; > > + qlink->next = prev_qlink; > > + } > > q->bytes += size; > > } > > > > @@ -121,7 +125,11 @@ static unsigned long quarantine_batch_size; > > * Quarantine doesn't support memory shrinker with SLAB allocator, so we keep > > * the ratio low to avoid OOM. > > */ > > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > > +#define QUARANTINE_FRACTION 128 > > Explain in a comment why we use lower value for sw tags mode. > The comment is below. "Tag-based KASAN only stores freed object information rather than the object itself. The quarantine in tag-based KASAN only needs less usage to achieve the same effect as generic KASAN. So We reduce the QUARANTINE_FRACTION value to slim the quarantine" > > +#else > > #define QUARANTINE_FRACTION 32 > > +#endif > > > > static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink) > > { > > @@ -139,16 +147,24 @@ static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache) > > > > static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) > > { > > - void *object = qlink_to_object(qlink, cache); > > unsigned long flags; > > + struct kmem_cache *obj_cache; > > + void *object; > > > > - if (IS_ENABLED(CONFIG_SLAB)) > > - local_irq_save(flags); > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS_IDENTIFY)) { > > + qobject_free(qlink, cache); > > + } else { > > + obj_cache = cache ? cache : qlink_to_cache(qlink); > > + object = qlink_to_object(qlink, obj_cache); > > > > - ___cache_free(cache, object, _THIS_IP_); > > + if (IS_ENABLED(CONFIG_SLAB)) > > + local_irq_save(flags); > > > > - if (IS_ENABLED(CONFIG_SLAB)) > > - local_irq_restore(flags); > > + ___cache_free(obj_cache, object, _THIS_IP_); > > + > > + if (IS_ENABLED(CONFIG_SLAB)) > > + local_irq_restore(flags); > > + } > > } > > > > static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) > > @@ -160,11 +176,9 @@ static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) > > > > qlink = q->head; > > while (qlink) { > > - struct kmem_cache *obj_cache = > > - cache ? cache : qlink_to_cache(qlink); > > struct qlist_node *next = qlink->next; > > > > - qlink_free(qlink, obj_cache); > > + qlink_free(qlink, cache); > > qlink = next; > > } > > qlist_init(q); > > @@ -175,6 +189,8 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache) > > unsigned long flags; > > struct qlist_head *q; > > struct qlist_head temp = QLIST_INIT; > > + struct kmem_cache *qobject_cache; > > + struct qlist_object *free_obj_info; > > > > /* > > * Note: irq must be disabled until after we move the batch to the > > @@ -187,7 +203,19 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache) > > local_irq_save(flags); > > > > q = this_cpu_ptr(&cpu_quarantine); > > - qlist_put(q, &info->quarantine_link, cache->size); > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS_IDENTIFY)) { > > + free_obj_info = qobject_create(info, cache); > > + if (!free_obj_info) { > > + local_irq_restore(flags); > > + return; > > + } > > + > > + qobject_cache = qlink_to_cache(&free_obj_info->qnode); > > + qlist_put(q, &free_obj_info->qnode, qobject_cache->size); > > We could use sizeof(*free_obj_info), which looks simpler. Any reason > to do another hop through the cache? > We originally thought we should store the whole slab usage(including metadata) instead of qobject size. If we use sizeof(*free_obj_info), then below calculation is incorrect. total quarantine size = (totalram_pages() << PAGE_SHIFT) / QUARANTINE_FRACTION - QUARANTINE_PERCPU_SIZE*num_online_cpus() > > + } else { > > + qlist_put(q, &info->quarantine_link, cache->size); > > + } > > + > > if (unlikely(q->bytes > QUARANTINE_PERCPU_SIZE)) { > > qlist_move_all(q, &temp); > > > > @@ -220,7 +248,6 @@ void quarantine_reduce(void) > > if (likely(READ_ONCE(quarantine_size) <= > > READ_ONCE(quarantine_max_size))) > > return; > > - > > /* > > * srcu critical section ensures that quarantine_remove_cache() > > * will not miss objects belonging to the cache while they are in our > > @@ -327,3 +354,90 @@ void quarantine_remove_cache(struct kmem_cache *cache) > > > > synchronize_srcu(&remove_cache_srcu); > > } > > + > > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > > +static noinline bool qlist_find_object(struct qlist_head *from, void *arg) > > +{ > > + struct qlist_node *curr; > > + struct qlist_object *curr_obj; > > + struct qlist_object *target = (struct qlist_object *)arg; > > + > > + if (unlikely(qlist_empty(from))) > > + return false; > > + > > + curr = from->head; > > + while (curr) { > > + struct qlist_node *next = curr->next; > > + > > + curr_obj = container_of(curr, struct qlist_object, qnode); > > + if (unlikely((target->addr >= curr_obj->addr) && > > + (target->addr < (curr_obj->addr + curr_obj->size)))) { > > + target->free_track = curr_obj->free_track; > > + return true; > > + } > > + > > + curr = next; > > + } > > + return false; > > +} > > + > > +static noinline int per_cpu_find_object(void *arg) > > +{ > > + struct qlist_head *q; > > + > > + q = this_cpu_ptr(&cpu_quarantine); > > + return qlist_find_object(q, arg); > > +} > > + > > +struct cpumask cpu_allowed_mask __read_mostly; > > + > > +bool quarantine_find_object(void *addr, struct kasan_track *free_track) > > +{ > > + unsigned long flags; > > + bool find = false; > > + int cpu, i; > > + struct qlist_object target; > > + > > + target.addr = (unsigned long)addr; > > + > > + cpumask_copy(&cpu_allowed_mask, cpu_online_mask); > > + for_each_cpu(cpu, &cpu_allowed_mask) { > > + find = smp_call_on_cpu(cpu, per_cpu_find_object, > > + (void *)&target, true); > > + if (find) { > > + if (free_track) > > + *free_track = target.free_track; > > + return true; > > + } > > + } > > + > > + raw_spin_lock_irqsave(&quarantine_lock, flags); > > + for (i = quarantine_tail; i >= 0; i--) { > > + if (qlist_empty(&global_quarantine[i])) > > + continue; > > + find = qlist_find_object(&global_quarantine[i], > > + (void *)&target); > > + if (find) { > > + if (free_track) > > + *free_track = target.free_track; > > + raw_spin_unlock_irqrestore(&quarantine_lock, flags); > > + return true; > > + } > > + } > > + for (i = QUARANTINE_BATCHES-1; i > quarantine_tail; i--) { > > Find a way to calculate the right index using a single loop, rather > that copy-paste the whole loop body to do a small adjustment to index. > single loop: for (i = quarantine_tail, j = 1; i != quarantine_tail || j != 2; i--) { if (i < 0) { i = QUARANTINE_BATCHES; j = 2; continue; } if (qlist_empty(&global_quarantine[i])) continue; find = qlist_find_object(&global_quarantine[i], (void *)&target); if (find) { if (free_track) *free_track = target.free_track; raw_spin_unlock_irqrestore(&quarantine_lock, flags); return true; } } > > + if (qlist_empty(&global_quarantine[i])) > > + continue; > > + find = qlist_find_object(&global_quarantine[i], > > + (void *)&target); > > + if (find) { > > + if (free_track) > > + *free_track = target.free_track; > > + raw_spin_unlock_irqrestore(&quarantine_lock, flags); > > + return true; > > + } > > + } > > + raw_spin_unlock_irqrestore(&quarantine_lock, flags); > > + > > + return false; > > +} > > +#endif > > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > > index ca9418fe9232..3cbc24cd3d43 100644 > > --- a/mm/kasan/report.c > > +++ b/mm/kasan/report.c > > @@ -150,18 +150,27 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, > > } > > > > static void describe_object(struct kmem_cache *cache, void *object, > > - const void *addr) > > + const void *tagged_addr) > > { > > + void *untagged_addr = reset_tag(tagged_addr); > > struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object); > > + struct kasan_track free_track; > > > > if (cache->flags & SLAB_KASAN) { > > - print_track(&alloc_info->alloc_track, "Allocated"); > > - pr_err("\n"); > > - print_track(&alloc_info->free_track, "Freed"); > > - pr_err("\n"); > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS_IDENTIFY) && > > + quarantine_find_object((void *)tagged_addr, > > + &free_track)) { > > + print_track(&free_track, "Freed"); > > + pr_err("\n"); > > + } else { > > + print_track(&alloc_info->alloc_track, "Allocated"); > > + pr_err("\n"); > > + print_track(&alloc_info->free_track, "Freed"); > > + pr_err("\n"); > > + } > > } > > > > - describe_object_addr(cache, object, addr); > > + describe_object_addr(cache, object, untagged_addr); > > } > > > > static inline bool kernel_or_module_addr(const void *addr) > > @@ -180,23 +189,25 @@ static inline bool init_task_stack_addr(const void *addr) > > sizeof(init_thread_union.stack)); > > } > > > > -static void print_address_description(void *addr) > > +static void print_address_description(void *tagged_addr) > > { > > - struct page *page = addr_to_page(addr); > > + void *untagged_addr = reset_tag(tagged_addr); > > + struct page *page = addr_to_page(untagged_addr); > > > > dump_stack(); > > pr_err("\n"); > > > > if (page && PageSlab(page)) { > > struct kmem_cache *cache = page->slab_cache; > > - void *object = nearest_obj(cache, page, addr); > > + void *object = nearest_obj(cache, page, untagged_addr); > > > > - describe_object(cache, object, addr); > > + describe_object(cache, object, tagged_addr); > > } > > > > - if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) { > > + if (kernel_or_module_addr(untagged_addr) && > > + !init_task_stack_addr(untagged_addr)) { > > pr_err("The buggy address belongs to the variable:\n"); > > - pr_err(" %pS\n", addr); > > + pr_err(" %pS\n", untagged_addr); > > } > > > > if (page) { > > @@ -314,7 +325,7 @@ void kasan_report(unsigned long addr, size_t size, > > pr_err("\n"); > > > > if (addr_has_shadow(untagged_addr)) { > > - print_address_description(untagged_addr); > > + print_address_description(tagged_addr); > > pr_err("\n"); > > print_shadow_for_address(info.first_bad_addr); > > } else { > > diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c > > index 63fca3172659..7804b48f760e 100644 > > --- a/mm/kasan/tags.c > > +++ b/mm/kasan/tags.c > > @@ -124,6 +124,53 @@ void check_memory_region(unsigned long addr, size_t size, bool write, > > } > > } > > > > +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY > > +void kasan_cache_shrink(struct kmem_cache *cache) > > +{ > > + quarantine_remove_cache(cache); > > This does not look to be necessary. There are no objects from that > cache in the quarantine in general. Let's not over-complicate this. > Ok, we will remove it. > > > > +} > > + > > +struct qlist_object *qobject_create(struct kasan_free_meta *info, > > + struct kmem_cache *cache) > > +{ > > + struct qlist_object *qobject_info; > > + void *object; > > + > > + object = ((void *)info) - cache->kasan_info.free_meta_offset; > > + qobject_info = kmalloc(sizeof(struct qlist_object), GFP_NOWAIT); > > + if (!qobject_info) > > + return NULL; > > + qobject_info->addr = (unsigned long) object; > > + qobject_info->size = cache->object_size; > > + set_track(&qobject_info->free_track, GFP_NOWAIT); > > + > > + return qobject_info; > > +} > > + > > +static struct kmem_cache *qobject_to_cache(struct qlist_object *qobject) > > +{ > > + return virt_to_head_page(qobject)->slab_cache; > > This looks identical to the existing qlink_to_cache, please use the > existing function. > > > +} > > + > > +void qobject_free(struct qlist_node *qlink, struct kmem_cache *cache) > > +{ > > + struct qlist_object *qobject = container_of(qlink, > > + struct qlist_object, qnode); > > + unsigned long flags; > > + > > + struct kmem_cache *qobject_cache = > > + cache ? cache : qobject_to_cache(qobject); > > I don't understand this part. > Will caller ever pass us the right cache? Or cache is always NULL? If > it's always NULL, why do we accept it at all? 2 call flow at v2. a). kmalloc() -> quarantine_reduce() -> qlist_free_all(&to_free, NULL) -> qlink_free(qlink, NULL) -> qobject_free(qlink, NULL) b). kmem_cache_shrink() -> kasan_cache_shrink(cache) -> quarantine_remove_cache() -> qlist_free_all(&to_free, cache); -> qlink_free(qlink, cache) -> qobject_free(qlink, cache) It passes the NULL parameter at flow a. It passes the cache of slab at flow b. We always need calculate the slab cache to If we remove flow b. > We also allocate qobjects with kmalloc always, so we must use kfree, > why do we even mess with caches? > We call ___cache_free() to free the qobject instead of kfree(), because it should be out of quarantine. > > + > > + if (IS_ENABLED(CONFIG_SLAB)) > > + local_irq_save(flags); > > + > > + ___cache_free(qobject_cache, (void *)qobject, _THIS_IP_); > > + > > + if (IS_ENABLED(CONFIG_SLAB)) > > + local_irq_restore(flags); > > +} > > +#endif > > + > > #define DEFINE_HWASAN_LOAD_STORE(size) \ > > void __hwasan_load##size##_noabort(unsigned long addr) \ > > { \ > > diff --git a/mm/kasan/tags_report.c b/mm/kasan/tags_report.c > > index 8eaf5f722271..63b0b1f381ff 100644 > > --- a/mm/kasan/tags_report.c > > +++ b/mm/kasan/tags_report.c > > @@ -36,7 +36,13 @@ > > > > const char *get_bug_type(struct kasan_access_info *info) > > { > > - return "invalid-access"; > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS_IDENTIFY)) { > > + if (quarantine_find_object((void *)info->access_addr, NULL)) > > + return "use-after-free"; > > + else > > + return "out-of-bounds"; > > + } else > > + return "invalid-access"; > > } > > > > void *find_first_bad_addr(void *addr, size_t size) > > diff --git a/mm/slub.c b/mm/slub.c > > index 1b08fbcb7e61..751429d02846 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -3004,7 +3004,7 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page, > > do_slab_free(s, page, head, tail, cnt, addr); > > } > > > > -#ifdef CONFIG_KASAN_GENERIC > > +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS_IDENTIFY) > > void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr) > > { > > do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel