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 43453C433F5 for ; Fri, 8 Apr 2022 12:32:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235768AbiDHMej (ORCPT ); Fri, 8 Apr 2022 08:34:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231622AbiDHMeg (ORCPT ); Fri, 8 Apr 2022 08:34:36 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B2681FFFA9 for ; Fri, 8 Apr 2022 05:32:32 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E5C04113E; Fri, 8 Apr 2022 05:32:31 -0700 (PDT) Received: from [10.57.9.161] (unknown [10.57.9.161]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CB9673F5A1; Fri, 8 Apr 2022 05:32:29 -0700 (PDT) Message-ID: <08e480cf-90d4-8225-1af9-fe187fc622be@arm.com> Date: Fri, 8 Apr 2022 13:32:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH] kasan: Fix hw tags enablement when KUNIT tests are disabled Content-Language: en-US To: Andrey Konovalov Cc: Linux ARM , LKML , kasan-dev , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , Catalin Marinas , Will Deacon References: <20220408100340.43620-1-vincenzo.frascino@arm.com> From: Vincenzo Frascino In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrey, On 4/8/22 1:26 PM, Andrey Konovalov wrote: > On Fri, Apr 8, 2022 at 12:04 PM Vincenzo Frascino > wrote: >> >> Kasan enables hw tags via kasan_enable_tagging() which based on the mode >> passed via kernel command line selects the correct hw backend. >> kasan_enable_tagging() is meant to be invoked indirectly via the cpu features >> framework of the architectures that support these backends. >> Currently the invocation of this function is guarded by CONFIG_KASAN_KUNIT_TEST >> which allows the enablement of the correct backend only when KUNIT tests are >> enabled in the kernel. > >> ... and prevents to enable MTE on arm64 when KUNIT tests for kasan hw_tags are >> disabled. > > Oh, indeed. Thanks for finding this! > >> This inconsistency was introduced in commit: >> >> f05842cfb9ae2 ("kasan, arm64: allow using KUnit tests with HW_TAGS mode") > > No, that commit is fine. The issue was introduced recently in > ed6d74446cbf ("kasan: test: support async (again) and asymm modes for > HW_TAGS"), where I changed kasan_init_hw_tags_cpu() to call > kasan_enable_tagging() instead of hw_enable_tagging_*(). > Thanks for pointing this out, the commit message above is referring to when the guard was introduced but I agree it is more correct to refer to when the logical issue was introduced. I will update it in v2. >> Fix the issue making sure that the CONFIG_KASAN_KUNIT_TEST guard does not >> prevent the correct invocation of kasan_enable_tagging(). >> >> Fixes: f05842cfb9ae2 ("kasan, arm64: allow using KUnit tests with HW_TAGS mode") >> Cc: Andrey Ryabinin >> Cc: Alexander Potapenko >> Cc: Andrey Konovalov >> Cc: Dmitry Vyukov >> Cc: Andrew Morton >> Cc: Catalin Marinas >> Cc: Will Deacon >> Signed-off-by: Vincenzo Frascino >> --- >> mm/kasan/hw_tags.c | 4 ++-- >> mm/kasan/kasan.h | 10 ++++++---- >> 2 files changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c >> index 07a76c46daa5..e2677501c36e 100644 >> --- a/mm/kasan/hw_tags.c >> +++ b/mm/kasan/hw_tags.c >> @@ -336,8 +336,6 @@ void __kasan_poison_vmalloc(const void *start, unsigned long size) >> >> #endif >> >> -#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) >> - >> void kasan_enable_tagging(void) >> { >> if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC) >> @@ -349,6 +347,8 @@ void kasan_enable_tagging(void) >> } >> EXPORT_SYMBOL_GPL(kasan_enable_tagging); > > Please keep this EXPORT_SYMBOL_GPL under CONFIG_KASAN_KUNIT_TEST. > Will do. Thanks! >> >> +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) >> + >> void kasan_force_async_fault(void) >> { >> hw_force_async_tag_fault(); >> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h >> index d79b83d673b1..b01b4bbe0409 100644 >> --- a/mm/kasan/kasan.h >> +++ b/mm/kasan/kasan.h >> @@ -355,25 +355,27 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) >> #define hw_set_mem_tag_range(addr, size, tag, init) \ >> arch_set_mem_tag_range((addr), (size), (tag), (init)) >> >> +void kasan_enable_tagging(void); >> + >> #else /* CONFIG_KASAN_HW_TAGS */ >> >> #define hw_enable_tagging_sync() >> #define hw_enable_tagging_async() >> #define hw_enable_tagging_asymm() >> >> +static inline void kasan_enable_tagging(void) { } >> + >> #endif /* CONFIG_KASAN_HW_TAGS */ >> >> #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) >> >> -void kasan_enable_tagging(void); >> void kasan_force_async_fault(void); >> >> -#else /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */ >> +#else /* CONFIG_KASAN_HW_TAGS && CONFIG_KASAN_KUNIT_TEST */ >> >> -static inline void kasan_enable_tagging(void) { } >> static inline void kasan_force_async_fault(void) { } >> >> -#endif /* CONFIG_KASAN_HW_TAGS || CONFIG_KASAN_KUNIT_TEST */ >> +#endif /* CONFIG_KASAN_HW_TAGS && CONFIG_KASAN_KUNIT_TEST */ >> >> #ifdef CONFIG_KASAN_SW_TAGS >> u8 kasan_random_tag(void); >> -- >> 2.35.1 >> > > Thank you, Vincenzo! -- Regards, Vincenzo