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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0FE44C433E0 for ; Fri, 5 Feb 2021 18:57:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B956864E30 for ; Fri, 5 Feb 2021 18:57:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233501AbhBERPX (ORCPT ); Fri, 5 Feb 2021 12:15:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:54516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233528AbhBEQCX (ORCPT ); Fri, 5 Feb 2021 11:02:23 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E93E464DD8; Fri, 5 Feb 2021 17:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612546988; bh=gEp/HvqPhB4Uqab3x0LzOie9DNxy6sj3uLcExSzDTDM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LAPnZVJ37/WzuxMH869sMvIY7ph4o3QHekVLpTk2ncmMXKhOOUo0/CsFIDTAFdaQv QwBCwBkT1ZZnqOC7227N8XkD8BquBVQrddXrMRwcCKGIlzSNT8BPm/eH+H580csyLb 1yC+AwxykX+mI5WKg9A8cLu0zpicSJItElROXEKm+PjTo0ut/dxdJMfs1G71pUYB3q SFie6QsjmNux3UXx62GwtxOoPFwrr/ZnamGcB/4tiVtCcE8l4GqBnkNJdUlrx4IkOO GG3vjgaBo5Lmb9aSQMZsZ79dMV95vNTjgoleK6pOXOcrZ2I74fUzbYrhU4PXcugaJk uB/H7/Wb1vL2w== Date: Fri, 5 Feb 2021 17:43:01 +0000 From: Will Deacon To: Andrey Konovalov Cc: Lecopzer Chen , Andrew Morton , Ard Biesheuvel , Andrey Ryabinin , Mark Brown , Catalin Marinas , Dan Williams , Dmitry Vyukov , Alexander Potapenko , gustavoars@kernel.org, kasan-dev , Lecopzer Chen , Linux ARM , LKML , "moderated list:ARM/Mediatek SoC..." , Linux Memory Management List , Guenter Roeck , Robin Murphy , rppt@kernel.org, tyhicks@linux.microsoft.com, Vincenzo Frascino , yj.chiang@mediatek.com Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC Message-ID: <20210205174301.GF22665@willie-the-truck> References: <20210204150100.GE20815@willie-the-truck> <20210204163721.91295-1-lecopzer@gmail.com> <20210205171859.GE22665@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 05, 2021 at 06:30:44PM +0100, Andrey Konovalov wrote: > On Fri, Feb 5, 2021 at 6:19 PM Will Deacon wrote: > > > > On Fri, Feb 05, 2021 at 12:37:21AM +0800, Lecopzer Chen wrote: > > > > > > > On Thu, Feb 04, 2021 at 10:46:12PM +0800, Lecopzer Chen wrote: > > > > > > On Sat, Jan 09, 2021 at 06:32:49PM +0800, Lecopzer Chen wrote: > > > > > > > Linux support KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > > > > > > ("kasan: support backing vmalloc space with real shadow memory") > > > > > > > > > > > > > > Like how the MODULES_VADDR does now, just not to early populate > > > > > > > the VMALLOC_START between VMALLOC_END. > > > > > > > similarly, the kernel code mapping is now in the VMALLOC area and > > > > > > > should keep these area populated. > > > > > > > > > > > > > > Signed-off-by: Lecopzer Chen > > > > > > > --- > > > > > > > arch/arm64/mm/kasan_init.c | 23 ++++++++++++++++++----- > > > > > > > 1 file changed, 18 insertions(+), 5 deletions(-) > > > > > > > > > > > > > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > > > > > > > index d8e66c78440e..39b218a64279 100644 > > > > > > > --- a/arch/arm64/mm/kasan_init.c > > > > > > > +++ b/arch/arm64/mm/kasan_init.c > > > > > > > @@ -214,6 +214,7 @@ static void __init kasan_init_shadow(void) > > > > > > > { > > > > > > > u64 kimg_shadow_start, kimg_shadow_end; > > > > > > > u64 mod_shadow_start, mod_shadow_end; > > > > > > > + u64 vmalloc_shadow_start, vmalloc_shadow_end; > > > > > > > phys_addr_t pa_start, pa_end; > > > > > > > u64 i; > > > > > > > > > > > > > > @@ -223,6 +224,9 @@ static void __init kasan_init_shadow(void) > > > > > > > mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR); > > > > > > > mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END); > > > > > > > > > > > > > > + vmalloc_shadow_start = (u64)kasan_mem_to_shadow((void *)VMALLOC_START); > > > > > > > + vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END); > > > > > > > + > > > > > > > /* > > > > > > > * We are going to perform proper setup of shadow memory. > > > > > > > * At first we should unmap early shadow (clear_pgds() call below). > > > > > > > @@ -241,12 +245,21 @@ static void __init kasan_init_shadow(void) > > > > > > > > > > > > > > kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END), > > > > > > > (void *)mod_shadow_start); > > > > > > > - kasan_populate_early_shadow((void *)kimg_shadow_end, > > > > > > > - (void *)KASAN_SHADOW_END); > > > > > > > + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { > > > > > > > > > > > > Do we really need yet another CONFIG option for KASAN? What's the use-case > > > > > > for *not* enabling this if you're already enabling one of the KASAN > > > > > > backends? > > > > > > > > > > As I know, KASAN_VMALLOC now only supports KASAN_GENERIC and also > > > > > KASAN_VMALLOC uses more memory to map real shadow memory (1/8 of vmalloc va). > > > > > > > > The shadow is allocated dynamically though, isn't it? > > > > > > Yes, but It's still a cost. > > > > > > > > There should be someone can enable KASAN_GENERIC but can't use VMALLOC > > > > > due to memory issue. > > > > > > > > That doesn't sound particularly realistic to me. The reason I'm pushing here > > > > is because I would _really_ like to move to VMAP stack unconditionally, and > > > > that would effectively force KASAN_VMALLOC to be set if KASAN is in use. > > > > > > > > So unless there's a really good reason not to do that, please can we make > > > > this unconditional for arm64? Pretty please? > > > > > > I think it's fine since we have a good reason. > > > Also if someone have memory issue in KASAN_VMALLOC, > > > they can use SW_TAG, right? > > > > > > However the SW_TAG/HW_TAG is not supported VMALLOC yet. > > > So the code would be like > > > > > > if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > > > > Just make this CONFIG_KASAN_VMALLOC, since that depends on KASAN_GENERIC. > > > > > /* explain the relationship between > > > * KASAN_GENERIC and KASAN_VMALLOC in arm64 > > > * XXX: because we want VMAP stack.... > > > */ > > > > I don't understand the relation with SW_TAGS. The VMAP_STACK dependency is: > > > > depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC > > This means that VMAP_STACK can be only enabled if KASAN_HW_TAGS=y or > if KASAN_VMALLOC=y for other modes. > > > > > which doesn't mention SW_TAGS at all. So that seems to imply that SW_TAGS > > and VMAP_STACK are mutually exclusive :( > > SW_TAGS doesn't yet have vmalloc support, so it's not compatible with > VMAP_STACK. Once vmalloc support is added to SW_TAGS, KASAN_VMALLOC > should be allowed to be enabled with SW_TAGS. This series is a step > towards having that support, but doesn't implement it. That will be a > separate effort. Ok, thanks. Then I think we should try to invert the dependency here, if possible, so that the KASAN backends depend on !VMAP_STACK if they don't support it, rather than silently disabling VMAP_STACK when they are selected. Will 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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 D60E4C433E0 for ; Fri, 5 Feb 2021 17:43:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 721BD64DD9 for ; Fri, 5 Feb 2021 17:43:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 721BD64DD9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 07B5C6B0075; 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Fri, 5 Feb 2021 17:43:09 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id E93E464DD8; Fri, 5 Feb 2021 17:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612546988; bh=gEp/HvqPhB4Uqab3x0LzOie9DNxy6sj3uLcExSzDTDM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LAPnZVJ37/WzuxMH869sMvIY7ph4o3QHekVLpTk2ncmMXKhOOUo0/CsFIDTAFdaQv QwBCwBkT1ZZnqOC7227N8XkD8BquBVQrddXrMRwcCKGIlzSNT8BPm/eH+H580csyLb 1yC+AwxykX+mI5WKg9A8cLu0zpicSJItElROXEKm+PjTo0ut/dxdJMfs1G71pUYB3q SFie6QsjmNux3UXx62GwtxOoPFwrr/ZnamGcB/4tiVtCcE8l4GqBnkNJdUlrx4IkOO GG3vjgaBo5Lmb9aSQMZsZ79dMV95vNTjgoleK6pOXOcrZ2I74fUzbYrhU4PXcugaJk uB/H7/Wb1vL2w== Date: Fri, 5 Feb 2021 17:43:01 +0000 From: Will Deacon To: Andrey Konovalov Cc: Lecopzer Chen , Andrew Morton , Ard Biesheuvel , Andrey Ryabinin , Mark Brown , Catalin Marinas , Dan Williams , Dmitry Vyukov , Alexander Potapenko , gustavoars@kernel.org, kasan-dev , Lecopzer Chen , Linux ARM , LKML , "moderated list:ARM/Mediatek SoC..." , Linux Memory Management List , Guenter Roeck , Robin Murphy , rppt@kernel.org, tyhicks@linux.microsoft.com, Vincenzo Frascino , yj.chiang@mediatek.com Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC Message-ID: <20210205174301.GF22665@willie-the-truck> References: <20210204150100.GE20815@willie-the-truck> <20210204163721.91295-1-lecopzer@gmail.com> <20210205171859.GE22665@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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: On Fri, Feb 05, 2021 at 06:30:44PM +0100, Andrey Konovalov wrote: > On Fri, Feb 5, 2021 at 6:19 PM Will Deacon wrote: > > > > On Fri, Feb 05, 2021 at 12:37:21AM +0800, Lecopzer Chen wrote: > > > > > > > On Thu, Feb 04, 2021 at 10:46:12PM +0800, Lecopzer Chen wrote: > > > > > > On Sat, Jan 09, 2021 at 06:32:49PM +0800, Lecopzer Chen wrote: > > > > > > > Linux support KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > > > > > > ("kasan: support backing vmalloc space with real shadow memory") > > > > > > > > > > > > > > Like how the MODULES_VADDR does now, just not to early populate > > > > > > > the VMALLOC_START between VMALLOC_END. > > > > > > > similarly, the kernel code mapping is now in the VMALLOC area and > > > > > > > should keep these area populated. > > > > > > > > > > > > > > Signed-off-by: Lecopzer Chen > > > > > > > --- > > > > > > > arch/arm64/mm/kasan_init.c | 23 ++++++++++++++++++----- > > > > > > > 1 file changed, 18 insertions(+), 5 deletions(-) > > > > > > > > > > > > > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > > > > > > > index d8e66c78440e..39b218a64279 100644 > > > > > > > --- a/arch/arm64/mm/kasan_init.c > > > > > > > +++ b/arch/arm64/mm/kasan_init.c > > > > > > > @@ -214,6 +214,7 @@ static void __init kasan_init_shadow(void) > > > > > > > { > > > > > > > u64 kimg_shadow_start, kimg_shadow_end; > > > > > > > u64 mod_shadow_start, mod_shadow_end; > > > > > > > + u64 vmalloc_shadow_start, vmalloc_shadow_end; > > > > > > > phys_addr_t pa_start, pa_end; > > > > > > > u64 i; > > > > > > > > > > > > > > @@ -223,6 +224,9 @@ static void __init kasan_init_shadow(void) > > > > > > > mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR); > > > > > > > mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END); > > > > > > > > > > > > > > + vmalloc_shadow_start = (u64)kasan_mem_to_shadow((void *)VMALLOC_START); > > > > > > > + vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END); > > > > > > > + > > > > > > > /* > > > > > > > * We are going to perform proper setup of shadow memory. > > > > > > > * At first we should unmap early shadow (clear_pgds() call below). > > > > > > > @@ -241,12 +245,21 @@ static void __init kasan_init_shadow(void) > > > > > > > > > > > > > > kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END), > > > > > > > (void *)mod_shadow_start); > > > > > > > - kasan_populate_early_shadow((void *)kimg_shadow_end, > > > > > > > - (void *)KASAN_SHADOW_END); > > > > > > > + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { > > > > > > > > > > > > Do we really need yet another CONFIG option for KASAN? What's the use-case > > > > > > for *not* enabling this if you're already enabling one of the KASAN > > > > > > backends? > > > > > > > > > > As I know, KASAN_VMALLOC now only supports KASAN_GENERIC and also > > > > > KASAN_VMALLOC uses more memory to map real shadow memory (1/8 of vmalloc va). > > > > > > > > The shadow is allocated dynamically though, isn't it? > > > > > > Yes, but It's still a cost. > > > > > > > > There should be someone can enable KASAN_GENERIC but can't use VMALLOC > > > > > due to memory issue. > > > > > > > > That doesn't sound particularly realistic to me. The reason I'm pushing here > > > > is because I would _really_ like to move to VMAP stack unconditionally, and > > > > that would effectively force KASAN_VMALLOC to be set if KASAN is in use. > > > > > > > > So unless there's a really good reason not to do that, please can we make > > > > this unconditional for arm64? Pretty please? > > > > > > I think it's fine since we have a good reason. > > > Also if someone have memory issue in KASAN_VMALLOC, > > > they can use SW_TAG, right? > > > > > > However the SW_TAG/HW_TAG is not supported VMALLOC yet. > > > So the code would be like > > > > > > if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > > > > Just make this CONFIG_KASAN_VMALLOC, since that depends on KASAN_GENERIC. > > > > > /* explain the relationship between > > > * KASAN_GENERIC and KASAN_VMALLOC in arm64 > > > * XXX: because we want VMAP stack.... > > > */ > > > > I don't understand the relation with SW_TAGS. The VMAP_STACK dependency is: > > > > depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC > > This means that VMAP_STACK can be only enabled if KASAN_HW_TAGS=y or > if KASAN_VMALLOC=y for other modes. > > > > > which doesn't mention SW_TAGS at all. So that seems to imply that SW_TAGS > > and VMAP_STACK are mutually exclusive :( > > SW_TAGS doesn't yet have vmalloc support, so it's not compatible with > VMAP_STACK. Once vmalloc support is added to SW_TAGS, KASAN_VMALLOC > should be allowed to be enabled with SW_TAGS. This series is a step > towards having that support, but doesn't implement it. That will be a > separate effort. Ok, thanks. Then I think we should try to invert the dependency here, if possible, so that the KASAN backends depend on !VMAP_STACK if they don't support it, rather than silently disabling VMAP_STACK when they are selected. Will 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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 1B77EC433DB for ; Fri, 5 Feb 2021 17:43:27 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 B03ED64DD9 for ; Fri, 5 Feb 2021 17:43:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B03ED64DD9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; 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Fri, 05 Feb 2021 17:43:15 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l858P-0007xY-WB; Fri, 05 Feb 2021 17:43:11 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id E93E464DD8; Fri, 5 Feb 2021 17:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612546988; bh=gEp/HvqPhB4Uqab3x0LzOie9DNxy6sj3uLcExSzDTDM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LAPnZVJ37/WzuxMH869sMvIY7ph4o3QHekVLpTk2ncmMXKhOOUo0/CsFIDTAFdaQv QwBCwBkT1ZZnqOC7227N8XkD8BquBVQrddXrMRwcCKGIlzSNT8BPm/eH+H580csyLb 1yC+AwxykX+mI5WKg9A8cLu0zpicSJItElROXEKm+PjTo0ut/dxdJMfs1G71pUYB3q SFie6QsjmNux3UXx62GwtxOoPFwrr/ZnamGcB/4tiVtCcE8l4GqBnkNJdUlrx4IkOO GG3vjgaBo5Lmb9aSQMZsZ79dMV95vNTjgoleK6pOXOcrZ2I74fUzbYrhU4PXcugaJk uB/H7/Wb1vL2w== Date: Fri, 5 Feb 2021 17:43:01 +0000 From: Will Deacon To: Andrey Konovalov Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC Message-ID: <20210205174301.GF22665@willie-the-truck> References: <20210204150100.GE20815@willie-the-truck> <20210204163721.91295-1-lecopzer@gmail.com> <20210205171859.GE22665@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210205_124310_252063_55F0DD5F X-CRM114-Status: GOOD ( 41.19 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lecopzer Chen , Catalin Marinas , LKML , Linux Memory Management List , tyhicks@linux.microsoft.com, Alexander Potapenko , Vincenzo Frascino , Ard Biesheuvel , yj.chiang@mediatek.com, kasan-dev , Dmitry Vyukov , Andrey Ryabinin , Guenter Roeck , Lecopzer Chen , Mark Brown , "moderated list:ARM/Mediatek SoC..." , Dan Williams , Linux ARM , gustavoars@kernel.org, Andrew Morton , Robin Murphy , rppt@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Fri, Feb 05, 2021 at 06:30:44PM +0100, Andrey Konovalov wrote: > On Fri, Feb 5, 2021 at 6:19 PM Will Deacon wrote: > > > > On Fri, Feb 05, 2021 at 12:37:21AM +0800, Lecopzer Chen wrote: > > > > > > > On Thu, Feb 04, 2021 at 10:46:12PM +0800, Lecopzer Chen wrote: > > > > > > On Sat, Jan 09, 2021 at 06:32:49PM +0800, Lecopzer Chen wrote: > > > > > > > Linux support KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > > > > > > ("kasan: support backing vmalloc space with real shadow memory") > > > > > > > > > > > > > > Like how the MODULES_VADDR does now, just not to early populate > > > > > > > the VMALLOC_START between VMALLOC_END. > > > > > > > similarly, the kernel code mapping is now in the VMALLOC area and > > > > > > > should keep these area populated. > > > > > > > > > > > > > > Signed-off-by: Lecopzer Chen > > > > > > > --- > > > > > > > arch/arm64/mm/kasan_init.c | 23 ++++++++++++++++++----- > > > > > > > 1 file changed, 18 insertions(+), 5 deletions(-) > > > > > > > > > > > > > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > > > > > > > index d8e66c78440e..39b218a64279 100644 > > > > > > > --- a/arch/arm64/mm/kasan_init.c > > > > > > > +++ b/arch/arm64/mm/kasan_init.c > > > > > > > @@ -214,6 +214,7 @@ static void __init kasan_init_shadow(void) > > > > > > > { > > > > > > > u64 kimg_shadow_start, kimg_shadow_end; > > > > > > > u64 mod_shadow_start, mod_shadow_end; > > > > > > > + u64 vmalloc_shadow_start, vmalloc_shadow_end; > > > > > > > phys_addr_t pa_start, pa_end; > > > > > > > u64 i; > > > > > > > > > > > > > > @@ -223,6 +224,9 @@ static void __init kasan_init_shadow(void) > > > > > > > mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR); > > > > > > > mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END); > > > > > > > > > > > > > > + vmalloc_shadow_start = (u64)kasan_mem_to_shadow((void *)VMALLOC_START); > > > > > > > + vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END); > > > > > > > + > > > > > > > /* > > > > > > > * We are going to perform proper setup of shadow memory. > > > > > > > * At first we should unmap early shadow (clear_pgds() call below). > > > > > > > @@ -241,12 +245,21 @@ static void __init kasan_init_shadow(void) > > > > > > > > > > > > > > kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END), > > > > > > > (void *)mod_shadow_start); > > > > > > > - kasan_populate_early_shadow((void *)kimg_shadow_end, > > > > > > > - (void *)KASAN_SHADOW_END); > > > > > > > + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { > > > > > > > > > > > > Do we really need yet another CONFIG option for KASAN? What's the use-case > > > > > > for *not* enabling this if you're already enabling one of the KASAN > > > > > > backends? > > > > > > > > > > As I know, KASAN_VMALLOC now only supports KASAN_GENERIC and also > > > > > KASAN_VMALLOC uses more memory to map real shadow memory (1/8 of vmalloc va). > > > > > > > > The shadow is allocated dynamically though, isn't it? > > > > > > Yes, but It's still a cost. > > > > > > > > There should be someone can enable KASAN_GENERIC but can't use VMALLOC > > > > > due to memory issue. > > > > > > > > That doesn't sound particularly realistic to me. The reason I'm pushing here > > > > is because I would _really_ like to move to VMAP stack unconditionally, and > > > > that would effectively force KASAN_VMALLOC to be set if KASAN is in use. > > > > > > > > So unless there's a really good reason not to do that, please can we make > > > > this unconditional for arm64? Pretty please? > > > > > > I think it's fine since we have a good reason. > > > Also if someone have memory issue in KASAN_VMALLOC, > > > they can use SW_TAG, right? > > > > > > However the SW_TAG/HW_TAG is not supported VMALLOC yet. > > > So the code would be like > > > > > > if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > > > > Just make this CONFIG_KASAN_VMALLOC, since that depends on KASAN_GENERIC. > > > > > /* explain the relationship between > > > * KASAN_GENERIC and KASAN_VMALLOC in arm64 > > > * XXX: because we want VMAP stack.... > > > */ > > > > I don't understand the relation with SW_TAGS. The VMAP_STACK dependency is: > > > > depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC > > This means that VMAP_STACK can be only enabled if KASAN_HW_TAGS=y or > if KASAN_VMALLOC=y for other modes. > > > > > which doesn't mention SW_TAGS at all. So that seems to imply that SW_TAGS > > and VMAP_STACK are mutually exclusive :( > > SW_TAGS doesn't yet have vmalloc support, so it's not compatible with > VMAP_STACK. Once vmalloc support is added to SW_TAGS, KASAN_VMALLOC > should be allowed to be enabled with SW_TAGS. This series is a step > towards having that support, but doesn't implement it. That will be a > separate effort. Ok, thanks. Then I think we should try to invert the dependency here, if possible, so that the KASAN backends depend on !VMAP_STACK if they don't support it, rather than silently disabling VMAP_STACK when they are selected. Will _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 16012C433E0 for ; Fri, 5 Feb 2021 17:44:30 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 A7C8464DD4 for ; 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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l858T-0007yl-Ru; Fri, 05 Feb 2021 17:43:13 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l858P-0007xY-WB; Fri, 05 Feb 2021 17:43:11 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id E93E464DD8; Fri, 5 Feb 2021 17:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612546988; bh=gEp/HvqPhB4Uqab3x0LzOie9DNxy6sj3uLcExSzDTDM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LAPnZVJ37/WzuxMH869sMvIY7ph4o3QHekVLpTk2ncmMXKhOOUo0/CsFIDTAFdaQv QwBCwBkT1ZZnqOC7227N8XkD8BquBVQrddXrMRwcCKGIlzSNT8BPm/eH+H580csyLb 1yC+AwxykX+mI5WKg9A8cLu0zpicSJItElROXEKm+PjTo0ut/dxdJMfs1G71pUYB3q SFie6QsjmNux3UXx62GwtxOoPFwrr/ZnamGcB/4tiVtCcE8l4GqBnkNJdUlrx4IkOO GG3vjgaBo5Lmb9aSQMZsZ79dMV95vNTjgoleK6pOXOcrZ2I74fUzbYrhU4PXcugaJk uB/H7/Wb1vL2w== Date: Fri, 5 Feb 2021 17:43:01 +0000 From: Will Deacon To: Andrey Konovalov Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC Message-ID: <20210205174301.GF22665@willie-the-truck> References: <20210204150100.GE20815@willie-the-truck> <20210204163721.91295-1-lecopzer@gmail.com> <20210205171859.GE22665@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210205_124310_252063_55F0DD5F X-CRM114-Status: GOOD ( 41.19 ) 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: Lecopzer Chen , Catalin Marinas , LKML , Linux Memory Management List , tyhicks@linux.microsoft.com, Alexander Potapenko , Vincenzo Frascino , Ard Biesheuvel , yj.chiang@mediatek.com, kasan-dev , Dmitry Vyukov , Andrey Ryabinin , Guenter Roeck , Lecopzer Chen , Mark Brown , "moderated list:ARM/Mediatek SoC..." , Dan Williams , Linux ARM , gustavoars@kernel.org, Andrew Morton , Robin Murphy , rppt@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Feb 05, 2021 at 06:30:44PM +0100, Andrey Konovalov wrote: > On Fri, Feb 5, 2021 at 6:19 PM Will Deacon wrote: > > > > On Fri, Feb 05, 2021 at 12:37:21AM +0800, Lecopzer Chen wrote: > > > > > > > On Thu, Feb 04, 2021 at 10:46:12PM +0800, Lecopzer Chen wrote: > > > > > > On Sat, Jan 09, 2021 at 06:32:49PM +0800, Lecopzer Chen wrote: > > > > > > > Linux support KAsan for VMALLOC since commit 3c5c3cfb9ef4da9 > > > > > > > ("kasan: support backing vmalloc space with real shadow memory") > > > > > > > > > > > > > > Like how the MODULES_VADDR does now, just not to early populate > > > > > > > the VMALLOC_START between VMALLOC_END. > > > > > > > similarly, the kernel code mapping is now in the VMALLOC area and > > > > > > > should keep these area populated. > > > > > > > > > > > > > > Signed-off-by: Lecopzer Chen > > > > > > > --- > > > > > > > arch/arm64/mm/kasan_init.c | 23 ++++++++++++++++++----- > > > > > > > 1 file changed, 18 insertions(+), 5 deletions(-) > > > > > > > > > > > > > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > > > > > > > index d8e66c78440e..39b218a64279 100644 > > > > > > > --- a/arch/arm64/mm/kasan_init.c > > > > > > > +++ b/arch/arm64/mm/kasan_init.c > > > > > > > @@ -214,6 +214,7 @@ static void __init kasan_init_shadow(void) > > > > > > > { > > > > > > > u64 kimg_shadow_start, kimg_shadow_end; > > > > > > > u64 mod_shadow_start, mod_shadow_end; > > > > > > > + u64 vmalloc_shadow_start, vmalloc_shadow_end; > > > > > > > phys_addr_t pa_start, pa_end; > > > > > > > u64 i; > > > > > > > > > > > > > > @@ -223,6 +224,9 @@ static void __init kasan_init_shadow(void) > > > > > > > mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR); > > > > > > > mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END); > > > > > > > > > > > > > > + vmalloc_shadow_start = (u64)kasan_mem_to_shadow((void *)VMALLOC_START); > > > > > > > + vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END); > > > > > > > + > > > > > > > /* > > > > > > > * We are going to perform proper setup of shadow memory. > > > > > > > * At first we should unmap early shadow (clear_pgds() call below). > > > > > > > @@ -241,12 +245,21 @@ static void __init kasan_init_shadow(void) > > > > > > > > > > > > > > kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END), > > > > > > > (void *)mod_shadow_start); > > > > > > > - kasan_populate_early_shadow((void *)kimg_shadow_end, > > > > > > > - (void *)KASAN_SHADOW_END); > > > > > > > + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { > > > > > > > > > > > > Do we really need yet another CONFIG option for KASAN? What's the use-case > > > > > > for *not* enabling this if you're already enabling one of the KASAN > > > > > > backends? > > > > > > > > > > As I know, KASAN_VMALLOC now only supports KASAN_GENERIC and also > > > > > KASAN_VMALLOC uses more memory to map real shadow memory (1/8 of vmalloc va). > > > > > > > > The shadow is allocated dynamically though, isn't it? > > > > > > Yes, but It's still a cost. > > > > > > > > There should be someone can enable KASAN_GENERIC but can't use VMALLOC > > > > > due to memory issue. > > > > > > > > That doesn't sound particularly realistic to me. The reason I'm pushing here > > > > is because I would _really_ like to move to VMAP stack unconditionally, and > > > > that would effectively force KASAN_VMALLOC to be set if KASAN is in use. > > > > > > > > So unless there's a really good reason not to do that, please can we make > > > > this unconditional for arm64? Pretty please? > > > > > > I think it's fine since we have a good reason. > > > Also if someone have memory issue in KASAN_VMALLOC, > > > they can use SW_TAG, right? > > > > > > However the SW_TAG/HW_TAG is not supported VMALLOC yet. > > > So the code would be like > > > > > > if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > > > > Just make this CONFIG_KASAN_VMALLOC, since that depends on KASAN_GENERIC. > > > > > /* explain the relationship between > > > * KASAN_GENERIC and KASAN_VMALLOC in arm64 > > > * XXX: because we want VMAP stack.... > > > */ > > > > I don't understand the relation with SW_TAGS. The VMAP_STACK dependency is: > > > > depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC > > This means that VMAP_STACK can be only enabled if KASAN_HW_TAGS=y or > if KASAN_VMALLOC=y for other modes. > > > > > which doesn't mention SW_TAGS at all. So that seems to imply that SW_TAGS > > and VMAP_STACK are mutually exclusive :( > > SW_TAGS doesn't yet have vmalloc support, so it's not compatible with > VMAP_STACK. Once vmalloc support is added to SW_TAGS, KASAN_VMALLOC > should be allowed to be enabled with SW_TAGS. This series is a step > towards having that support, but doesn't implement it. That will be a > separate effort. Ok, thanks. Then I think we should try to invert the dependency here, if possible, so that the KASAN backends depend on !VMAP_STACK if they don't support it, rather than silently disabling VMAP_STACK when they are selected. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel