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=-16.5 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 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 AE4BEC433E0 for ; Wed, 3 Feb 2021 18:37:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C70D64E34 for ; Wed, 3 Feb 2021 18:37:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C70D64E34 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 C0CA16B0005; Wed, 3 Feb 2021 13:37:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BBE1C6B0006; Wed, 3 Feb 2021 13:37:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD32B6B006E; Wed, 3 Feb 2021 13:37:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id 979C36B0005 for ; Wed, 3 Feb 2021 13:37:40 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6C3C5181AEF1D for ; Wed, 3 Feb 2021 18:37:39 +0000 (UTC) X-FDA: 77777815038.08.D494936 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf04.hostedemail.com (Postfix) with ESMTP id 3A8FE13A for ; Wed, 3 Feb 2021 18:37:31 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id B456064DE1 for ; Wed, 3 Feb 2021 18:37:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612377450; bh=3giaFRH1j9PVmzyZwv3HjY0DTQs3tZkZzQ8m1nc4mNg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=UKpOsqrXPhh2J4MabEYv9pDGdajv4XjOL7hpTw2yiP+4kYP4oJo8FVd0iHO6eLA+d uUxt+1U0/Y7RFnuzOGAQigFDWYuTKbC5dVhZk71coTGV5MT/IX8PoN+8XQMsXlEuy/ DSEFwVrLUmKKZtoy3KCaPhjNzA2hdantHnAHWC91GpHYfiYKawj/Hw/xGFrWs3qwSb buJ0AhEwkX3UXUOmaxEF+DNxV2KP7lfRUNJbTCxWYNp8/PqOoJJ3DZ0Gucefn8UIQl 2vNbkpA8mw7Z+kmelm61kFgflvIjghJU/9bNHmQ3YZZabrpJNCdv4T6b1Tuf/XUaJO fuCqWe4BgPnWg== Received: by mail-oi1-f178.google.com with SMTP id d20so883698oiw.10 for ; Wed, 03 Feb 2021 10:37:30 -0800 (PST) X-Gm-Message-State: AOAM53361ozCUNJ46jGyb2aZZbW8v93G0ALRvf8JFuNYhWZydqxJk627 R+wwhEiWmESv4hyMyNqIU5obZs7WK/zkw/rVWDA= X-Google-Smtp-Source: ABdhPJwTcKGhhrhcSXeU83MadiHuFOevZ5EXyyScTqYjD6/o+QLIP4TAi8X/UM98hvguCOQr900onLCBTaId+ZK8RP4= X-Received: by 2002:aca:ea0b:: with SMTP id i11mr2899751oih.33.1612377449888; Wed, 03 Feb 2021 10:37:29 -0800 (PST) MIME-Version: 1.0 References: <20210109103252.812517-1-lecopzer@gmail.com> <20210109103252.812517-2-lecopzer@gmail.com> In-Reply-To: <20210109103252.812517-2-lecopzer@gmail.com> From: Ard Biesheuvel Date: Wed, 3 Feb 2021 19:37:18 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC To: Lecopzer Chen Cc: Linux Kernel Mailing List , Linux Memory Management List , kasan-dev , Linux ARM , Dan Williams , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , linux-mediatek@lists.infradead.org, yj.chiang@mediatek.com, Will Deacon , Catalin Marinas , Andrey Konovalov , Mark Brown , Guenter Roeck , Mike Rapoport , Tyler Hicks , Robin Murphy , Vincenzo Frascino , "Gustavo A. R. Silva" , Lecopzer Chen Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 3A8FE13A X-Stat-Signature: btf4b3gacfxhguz5nbytwqrgpbjm4bio Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf04; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1612377451-509910 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 Sat, 9 Jan 2021 at 11:33, 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 This commit log text is a bit hard to follow. You are saying that the vmalloc region is *not* backed with zero shadow or any default mapping at all, right, and everything gets allocated on demand, just like is the case for modules? > --- > 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); > + This and the below seems overly complicated, given that VMALLOC_START == MODULES_END. Can we simplify this? > /* > * 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)) { > + kasan_populate_early_shadow((void *)vmalloc_shadow_end, > + (void *)KASAN_SHADOW_END); > + if (vmalloc_shadow_start > mod_shadow_end) > + kasan_populate_early_shadow((void *)mod_shadow_end, > + (void *)vmalloc_shadow_start); > + > + } else { > + kasan_populate_early_shadow((void *)kimg_shadow_end, > + (void *)KASAN_SHADOW_END); > + if (kimg_shadow_start > mod_shadow_end) > + kasan_populate_early_shadow((void *)mod_shadow_end, > + (void *)kimg_shadow_start); > + } > > - if (kimg_shadow_start > mod_shadow_end) > - kasan_populate_early_shadow((void *)mod_shadow_end, > - (void *)kimg_shadow_start); > > for_each_mem_range(i, &pa_start, &pa_end) { > void *start = (void *)__phys_to_virt(pa_start); > -- > 2.25.1 >