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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 E2DFFC55178 for ; Wed, 4 Nov 2020 23:48:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A5032075E for ; Wed, 4 Nov 2020 23:48:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sK1NO5++" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387657AbgKDXsk (ORCPT ); Wed, 4 Nov 2020 18:48:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732678AbgKDXsi (ORCPT ); Wed, 4 Nov 2020 18:48:38 -0500 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4900DC0613CF for ; Wed, 4 Nov 2020 15:48:38 -0800 (PST) Received: by mail-pf1-x442.google.com with SMTP id b3so14864pfo.2 for ; Wed, 04 Nov 2020 15:48:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wp+w8b4AFAXGjQKKBQtaL9VCmaHHu9rnir4s+oQgV0I=; b=sK1NO5++vK5I08U1DMSQu79mhNHqHghpRSSGLa90mNfc4eRl+usqPTRolBsW7EW1ei TtGEeZSaZ5jCIkTSuWVdovvMOtIepKKsbVWNLmjvCST4/we792ohe7rtJfSysrellroW e6zOBAMyi7wpqgaCLV8F/5UNENhn0KwPuQGMWSasd23xCDIpayQPW0aJ9vMTezMYXYSY Li3g6Conp/qJHYVA//E21WH6+QV/NLu9JPVNiErHZF15MEt7tI3GyxQl2+ablkMkSaGU D3mXrqJ5qRhcJgaVSLYYNmH3pQ43oGKmevVyQ/q+m05g97gYt6zviTNkYAGCgV8FsrdX rqNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wp+w8b4AFAXGjQKKBQtaL9VCmaHHu9rnir4s+oQgV0I=; b=YblSKCChVxViDqmvVqS0CHV4nIWhR224aR0eYwtTynRNjhrRNjUg5Ig4QxwY9breOK 4fVKnbB8tuf+AZ1XEezjjWyYnjr16WHR7s1XITulUt0JsCUO/5cdTgv5vT7XXT8qwp0P u65LtXf4ZJLvBVH9NbeTu/zW0FshTu7ldrSl9PHLsCfAUfcUiLEqIbUYcZ0XsC3ZeQOn 9g1CYDIAHIickc+zcQ/Al8A0VKd0yyQ8/ABQVQTpjkEs00aWwipPJRvYp3jad6ddXN+P HeXZwJdbwuA3auxxxlz8tye8J8yKEAMI5BLWxCMDjRoe6Ob6a8fNUEjYEGyYNjpYvLUD 7wAA== X-Gm-Message-State: AOAM53280ZMEKf4CBoMcEsYlpFAULqD6vuBFk4GpqrmzSVt2maljbN4J 2dlKVCfQ3AvB3PWt25nrKRd11l77CyVxNNBJ4oIfbA== X-Google-Smtp-Source: ABdhPJxFXTtnwpjLL8ThTQ2Xu0GZmCyNnZahX63GjeD4f29lltR8i7tLND9dBR6pnkmDADyx+I0PgQrjpMiuujwKsMY= X-Received: by 2002:a17:90a:eb02:: with SMTP id j2mr332535pjz.136.1604533717527; Wed, 04 Nov 2020 15:48:37 -0800 (PST) MIME-Version: 1.0 References: <9b0c00ddb76e15cdcd86e12f85ce4f8a5e946299.1604531793.git.andreyknvl@google.com> In-Reply-To: <9b0c00ddb76e15cdcd86e12f85ce4f8a5e946299.1604531793.git.andreyknvl@google.com> From: Andrey Konovalov Date: Thu, 5 Nov 2020 00:48:26 +0100 Message-ID: Subject: Re: [PATCH v8 38/43] kasan, arm64: implement HW_TAGS runtime To: Catalin Marinas Cc: Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 5, 2020 at 12:20 AM Andrey Konovalov wrote: > > Provide implementation of KASAN functions required for the hardware > tag-based mode. Those include core functions for memory and pointer > tagging (tags_hw.c) and bug reporting (report_tags_hw.c). Also adapt > common KASAN code to support the new mode. > > Signed-off-by: Andrey Konovalov > Signed-off-by: Vincenzo Frascino > Acked-by: Catalin Marinas > --- > Change-Id: I8a8689ba098174a4d0ef3f1d008178387c80ee1c > --- > arch/arm64/include/asm/memory.h | 4 +- > arch/arm64/kernel/cpufeature.c | 3 ++ > include/linux/kasan.h | 22 ++++++--- > include/linux/mm.h | 2 +- > include/linux/page-flags-layout.h | 2 +- > mm/kasan/Makefile | 5 ++ > mm/kasan/common.c | 15 +++--- > mm/kasan/hw_tags.c | 76 +++++++++++++++++++++++++++++++ > mm/kasan/kasan.h | 17 +++++-- > mm/kasan/report_hw_tags.c | 42 +++++++++++++++++ > mm/kasan/report_sw_tags.c | 2 +- > mm/kasan/shadow.c | 2 +- > mm/kasan/sw_tags.c | 2 +- > 13 files changed, 169 insertions(+), 25 deletions(-) > create mode 100644 mm/kasan/hw_tags.c > create mode 100644 mm/kasan/report_hw_tags.c > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 507012ed24f4..b245554984a2 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -214,7 +214,7 @@ static inline unsigned long kaslr_offset(void) > (__force __typeof__(addr))__addr; \ > }) > > -#ifdef CONFIG_KASAN_SW_TAGS > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > #define __tag_shifted(tag) ((u64)(tag) << 56) > #define __tag_reset(addr) __untagged_addr(addr) > #define __tag_get(addr) (__u8)((u64)(addr) >> 56) > @@ -222,7 +222,7 @@ static inline unsigned long kaslr_offset(void) > #define __tag_shifted(tag) 0UL > #define __tag_reset(addr) (addr) > #define __tag_get(addr) 0 > -#endif /* CONFIG_KASAN_SW_TAGS */ > +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > > static inline const void *__tag_set(const void *addr, u8 tag) > { > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index dcc165b3fc04..b66a96525a3e 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -70,6 +70,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -1704,6 +1705,8 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap) > cleared_zero_page = true; > mte_clear_page_tags(lm_alias(empty_zero_page)); > } > + > + kasan_init_hw_tags(); > } > #endif /* CONFIG_ARM64_MTE */ > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index beb699e90e55..c6bf762eb88c 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -187,25 +187,33 @@ static inline void kasan_record_aux_stack(void *ptr) {} > > #endif /* CONFIG_KASAN_GENERIC */ > > -#ifdef CONFIG_KASAN_SW_TAGS > - > -void __init kasan_init_sw_tags(void); > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > > void *kasan_reset_tag(const void *addr); > > bool kasan_report(unsigned long addr, size_t size, > bool is_write, unsigned long ip); > > -#else /* CONFIG_KASAN_SW_TAGS */ > - > -static inline void kasan_init_sw_tags(void) { } > +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > > static inline void *kasan_reset_tag(const void *addr) > { > return (void *)addr; > } > > -#endif /* CONFIG_KASAN_SW_TAGS */ > +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS*/ > + > +#ifdef CONFIG_KASAN_SW_TAGS > +void __init kasan_init_sw_tags(void); > +#else > +static inline void kasan_init_sw_tags(void) { } > +#endif > + > +#ifdef CONFIG_KASAN_HW_TAGS > +void __init kasan_init_hw_tags(void); > +#else > +static inline void kasan_init_hw_tags(void) { } > +#endif > > #ifdef CONFIG_KASAN_VMALLOC > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index db6ae4d3fb4e..0793d03a4183 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1413,7 +1413,7 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid) > } > #endif /* CONFIG_NUMA_BALANCING */ > > -#ifdef CONFIG_KASAN_SW_TAGS > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > static inline u8 page_kasan_tag(const struct page *page) > { > return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; > diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h > index e200eef6a7fd..7d4ec26d8a3e 100644 > --- a/include/linux/page-flags-layout.h > +++ b/include/linux/page-flags-layout.h > @@ -77,7 +77,7 @@ > #define LAST_CPUPID_SHIFT 0 > #endif > > -#ifdef CONFIG_KASAN_SW_TAGS > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > #define KASAN_TAG_WIDTH 8 > #else > #define KASAN_TAG_WIDTH 0 > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > index f1d68a34f3c9..9fe39a66388a 100644 > --- a/mm/kasan/Makefile > +++ b/mm/kasan/Makefile > @@ -10,8 +10,10 @@ CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_quarantine.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_report_generic.o = $(CC_FLAGS_FTRACE) > +CFLAGS_REMOVE_report_hw_tags.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_report_sw_tags.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE) > +CFLAGS_REMOVE_hw_tags.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_sw_tags.o = $(CC_FLAGS_FTRACE) > > # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 > @@ -27,10 +29,13 @@ CFLAGS_init.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_quarantine.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_report_generic.o := $(CC_FLAGS_KASAN_RUNTIME) > +CFLAGS_report_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_report_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_shadow.o := $(CC_FLAGS_KASAN_RUNTIME) > +CFLAGS_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) > CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) > > obj-$(CONFIG_KASAN) := common.o report.o > obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o > +obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o > obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index d0b3ff410b0c..2bb0ef6da6bd 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -113,7 +113,7 @@ void kasan_free_pages(struct page *page, unsigned int order) > */ > static inline unsigned int optimal_redzone(unsigned int object_size) > { > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > + if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) > return 0; > > return > @@ -178,14 +178,14 @@ size_t kasan_metadata_size(struct kmem_cache *cache) > struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, > const void *object) > { > - return (void *)object + cache->kasan_info.alloc_meta_offset; > + return (void *)reset_tag(object) + cache->kasan_info.alloc_meta_offset; > } > > struct kasan_free_meta *get_free_info(struct kmem_cache *cache, > const void *object) > { > BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); > - return (void *)object + cache->kasan_info.free_meta_offset; > + return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset; > } > > void kasan_poison_slab(struct page *page) > @@ -267,9 +267,8 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > alloc_info = get_alloc_info(cache, object); > __memset(alloc_info, 0, sizeof(*alloc_info)); > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > - object = set_tag(object, > - assign_tag(cache, object, true, false)); > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > + object = set_tag(object, assign_tag(cache, object, true, false)); > > return (void *)object; > } > @@ -337,10 +336,10 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > redzone_end = round_up((unsigned long)object + cache->object_size, > KASAN_GRANULE_SIZE); > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > tag = assign_tag(cache, object, false, keep_tag); > > - /* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */ > + /* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */ > kasan_unpoison_memory(set_tag(object, tag), size); > kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start, > KASAN_KMALLOC_REDZONE); > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > new file mode 100644 > index 000000000000..bdb684c65561 > --- /dev/null > +++ b/mm/kasan/hw_tags.c > @@ -0,0 +1,76 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file contains core hardware tag-based KASAN code. > + * > + * Copyright (c) 2020 Google, Inc. > + * Author: Andrey Konovalov > + */ > + > +#define pr_fmt(fmt) "kasan: " fmt > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "kasan.h" > + > +/* kasan_init_hw_tags() is called for each CPU. */ > +void __init kasan_init_hw_tags(void) This should not be __init, forgot to include this change. > +{ > + hw_init_tags(KASAN_TAG_MAX); > + > + if (smp_processor_id() == 0) > + pr_info("KernelAddressSanitizer initialized\n"); > +} > + > +void *kasan_reset_tag(const void *addr) > +{ > + return reset_tag(addr); > +} > + > +void kasan_poison_memory(const void *address, size_t size, u8 value) > +{ > + hw_set_mem_tag_range(reset_tag(address), > + round_up(size, KASAN_GRANULE_SIZE), value); > +} > + > +void kasan_unpoison_memory(const void *address, size_t size) > +{ > + hw_set_mem_tag_range(reset_tag(address), > + round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); > +} > + > +u8 random_tag(void) > +{ > + return hw_get_random_tag(); > +} > + > +bool check_invalid_free(void *addr) > +{ > + u8 ptr_tag = get_tag(addr); > + u8 mem_tag = hw_get_mem_tag(addr); > + > + return (mem_tag == KASAN_TAG_INVALID) || > + (ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag); > +} > + > +void kasan_set_free_info(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + struct kasan_alloc_meta *alloc_meta; > + > + alloc_meta = get_alloc_info(cache, object); > + kasan_set_track(&alloc_meta->free_track[0], GFP_NOWAIT); > +} > + > +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, > + void *object, u8 tag) > +{ > + struct kasan_alloc_meta *alloc_meta; > + > + alloc_meta = get_alloc_info(cache, object); > + return &alloc_meta->free_track[0]; > +} > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index 618e69d12f61..b0a57d8f9803 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -153,6 +153,10 @@ struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, > struct kasan_free_meta *get_free_info(struct kmem_cache *cache, > const void *object); > > +void kasan_poison_memory(const void *address, size_t size, u8 value); > + > +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) > + > static inline const void *kasan_shadow_to_mem(const void *shadow_addr) > { > return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET) > @@ -164,8 +168,6 @@ static inline bool addr_has_metadata(const void *addr) > return (addr >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); > } > > -void kasan_poison_memory(const void *address, size_t size, u8 value); > - > /** > * check_memory_region - Check memory region, and report if invalid access. > * @addr: the accessed address > @@ -177,6 +179,15 @@ void kasan_poison_memory(const void *address, size_t size, u8 value); > bool check_memory_region(unsigned long addr, size_t size, bool write, > unsigned long ret_ip); > > +#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ > + > +static inline bool addr_has_metadata(const void *addr) > +{ > + return PageSlab(virt_to_head_page(addr)); > +} > + > +#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ > + > bool check_invalid_free(void *addr); > > void *find_first_bad_addr(void *addr, size_t size); > @@ -213,7 +224,7 @@ static inline void quarantine_reduce(void) { } > static inline void quarantine_remove_cache(struct kmem_cache *cache) { } > #endif > > -#ifdef CONFIG_KASAN_SW_TAGS > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > > void print_tags(u8 addr_tag, const void *addr); > > diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c > new file mode 100644 > index 000000000000..da543eb832cd > --- /dev/null > +++ b/mm/kasan/report_hw_tags.c > @@ -0,0 +1,42 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file contains hardware tag-based KASAN specific error reporting code. > + * > + * Copyright (c) 2020 Google, Inc. > + * Author: Andrey Konovalov > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "kasan.h" > + > +const char *get_bug_type(struct kasan_access_info *info) > +{ > + return "invalid-access"; > +} > + > +void *find_first_bad_addr(void *addr, size_t size) > +{ > + return reset_tag(addr); > +} > + > +void metadata_fetch_row(char *buffer, void *row) > +{ > + int i; > + > + for (i = 0; i < META_BYTES_PER_ROW; i++) > + buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE); > +} > + > +void print_tags(u8 addr_tag, const void *addr) > +{ > + u8 memory_tag = hw_get_mem_tag((void *)addr); > + > + pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", > + addr_tag, memory_tag); > +} > diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c > index add2dfe6169c..aebc44a29e83 100644 > --- a/mm/kasan/report_sw_tags.c > +++ b/mm/kasan/report_sw_tags.c > @@ -1,6 +1,6 @@ > // SPDX-License-Identifier: GPL-2.0 > /* > - * This file contains tag-based KASAN specific error reporting code. > + * This file contains software tag-based KASAN specific error reporting code. > * > * Copyright (c) 2014 Samsung Electronics Co., Ltd. > * Author: Andrey Ryabinin > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > index 1fadd4930d54..616ac64c4a21 100644 > --- a/mm/kasan/shadow.c > +++ b/mm/kasan/shadow.c > @@ -107,7 +107,7 @@ void kasan_unpoison_memory(const void *address, size_t size) > > if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > *shadow = tag; > - else > + else /* CONFIG_KASAN_GENERIC */ > *shadow = size & KASAN_GRANULE_MASK; > } > } > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c > index b09a2c06abad..dfe707dd8d0d 100644 > --- a/mm/kasan/sw_tags.c > +++ b/mm/kasan/sw_tags.c > @@ -1,6 +1,6 @@ > // SPDX-License-Identifier: GPL-2.0 > /* > - * This file contains core tag-based KASAN code. > + * This file contains core software tag-based KASAN code. > * > * Copyright (c) 2018 Google, Inc. > * Author: Andrey Konovalov > -- > 2.29.1.341.ge80a0c044ae-goog >