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Thu, 4 Feb 2021 12:45:52 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 4FBF664F41; Thu, 4 Feb 2021 12:45:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612442751; bh=SOnQy9RxOKww3FwtcmXtlNIaVMdG5cK/YIx9GSd2M48=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dG/U0a+xaSr261uO6Sj/SU5bdTLBoZ8g1XHARG/8dEABI3D4ZPIyOFPS/QsysXGC2 sZL7qauWqARMR6/bElBXzMasqAVx7p+ROhtZo2MKsyJaSoC74GT2fIPx3k8IoZSmyP YdzMr2K1eqnkENuzQNKlHpf6xx85c1+DE2elfQPasxfufiZWCbjkTDFGnGWQbqed/U hbVmNI6p0caFF0aecWklnKLhjQRWPEdIqf9YoOlZXmZXhmHAWttM7hnzi+q0o3JtRD iT67+pIC457vEjSd2+iCbh6VuUGvW/Erpqqh2Z5Euu66XtJbknR93QiqmbvasIrGvU EJ4ggbI1KF9rA== Date: Thu, 4 Feb 2021 12:45:43 +0000 From: Will Deacon To: Lecopzer Chen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, dan.j.williams@intel.com, aryabinin@virtuozzo.com, glider@google.com, dvyukov@google.com, akpm@linux-foundation.org, linux-mediatek@lists.infradead.org, yj.chiang@mediatek.com, catalin.marinas@arm.com, ardb@kernel.org, andreyknvl@google.com, broonie@kernel.org, linux@roeck-us.net, rppt@kernel.org, tyhicks@linux.microsoft.com, robin.murphy@arm.com, vincenzo.frascino@arm.com, gustavoars@kernel.org, Lecopzer Chen Subject: Re: [PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC Message-ID: <20210204124543.GA20468@willie-the-truck> References: <20210109103252.812517-1-lecopzer@gmail.com> <20210109103252.812517-2-lecopzer@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210109103252.812517-2-lecopzer@gmail.com> 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 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? > + kasan_populate_early_shadow((void *)vmalloc_shadow_end, > + (void *)KASAN_SHADOW_END); > + if (vmalloc_shadow_start > mod_shadow_end) To echo Ard's concern: when is the above 'if' condition true? Will