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, 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 4928FC43461 for ; Fri, 11 Sep 2020 07:05:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B182F221F1 for ; Fri, 11 Sep 2020 07:05:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="l6I1g9C1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B182F221F1 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BDE25900004; Fri, 11 Sep 2020 03:05:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B8C836B0096; Fri, 11 Sep 2020 03:05:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A7C31900004; Fri, 11 Sep 2020 03:05:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0047.hostedemail.com [216.40.44.47]) by kanga.kvack.org (Postfix) with ESMTP id 93D1A6B007B for ; Fri, 11 Sep 2020 03:05:07 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4825A362B for ; Fri, 11 Sep 2020 07:05:07 +0000 (UTC) X-FDA: 77249893854.29.sheet72_120efd1270ec Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 27689180868D1 for ; Fri, 11 Sep 2020 07:05:07 +0000 (UTC) X-HE-Tag: sheet72_120efd1270ec X-Filterd-Recvd-Size: 7036 Received: from mail-qv1-f68.google.com (mail-qv1-f68.google.com [209.85.219.68]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Fri, 11 Sep 2020 07:05:06 +0000 (UTC) Received: by mail-qv1-f68.google.com with SMTP id b13so4715294qvl.2 for ; Fri, 11 Sep 2020 00:05:06 -0700 (PDT) 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=8qYTA7a/mDb0x7v76SumPW6fQ7bLMrnrWY5ltUv9JNU=; b=l6I1g9C1SvoJBjGEU0JNeOK0OUWWHuh+ALTBHG8Q61JGEqU4KeeE5IlLbk4bq+biRP GLthBBCFLV74aP/hQaHI2M0uCtoZz+JpOo4lFoxKTjE1iW7bCuJswGKKAlv+zaA9qnkp TlS1NPVdFNmHAqjPSNR659dB1WOgl7sIIp5R9vb7NnibPcG7TDweMFV/AUK/qXe6Nlww O3k9zPK1DfyWXuhengm0F807rZ57VgNbELKS6QRJ5VAQEYFRAIBEj+paw0bj8u/keVzB +KusOeic/b8Aqz8saD0zP8EvoIS5TolTvFwZtAgF/VFApLsHX/JUnGw3O8psBt3RKhyr ibtQ== 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=8qYTA7a/mDb0x7v76SumPW6fQ7bLMrnrWY5ltUv9JNU=; b=jiJ1cBRDYqetqNypuVXjEDNalG46uQuckMGzuyniHOMB2VVw8zAVIYrnhVGldvCsrz mDK+qUrkqcOg2Q/IC/BP2tIOKUqSBD2owGwUVYSKQJgNBYCv4sk9JCptJCMS3rDXrBCG xT7lW2CkuFoIw2SMUsCbVoHa8bC+XieLk3dzu6RiRaarS0PgWyWijIt8+gRHFzvQ7xSJ MnpWQSfMqmDDz4fNQMjrRqS5B3CjNDyvq75K6WyqINVMbyxQU674yhEnyVi9qD779ddZ Mxkvkblsym4WBEx/wGBgQo+VEvf16Qsn3LzkFjJyf8m2duKaOG6tzbyh08/mHF8lERvS jCzg== X-Gm-Message-State: AOAM5338qFs9zzOodyAMdUrwfEYJG8D23jpANG7AcTX8KnfEyaPZCl4O iIqnTDl4skmGY6fg0CceH8f6xGN3QLUSAyl8gnFOhw== X-Google-Smtp-Source: ABdhPJwPLAUEsAzaSMCLt+v28C4/YXeXs4UpRMTYz0l4idhp0Mt0npwu+vanlcme90OTrVPya2wrVj/k/dc78p5FmYU= X-Received: by 2002:a0c:c24a:: with SMTP id w10mr609462qvh.99.1599807905731; Fri, 11 Sep 2020 00:05:05 -0700 (PDT) MIME-Version: 1.0 References: <20200907134055.2878499-1-elver@google.com> <20200907134055.2878499-7-elver@google.com> In-Reply-To: <20200907134055.2878499-7-elver@google.com> From: Dmitry Vyukov Date: Fri, 11 Sep 2020 09:04:54 +0200 Message-ID: Subject: Re: [PATCH RFC 06/10] kfence, kasan: make KFENCE compatible with KASAN To: Marco Elver Cc: Alexander Potapenko , Andrew Morton , Catalin Marinas , Christoph Lameter , David Rientjes , Joonsoo Kim , Mark Rutland , Pekka Enberg , "H. Peter Anvin" , "Paul E. McKenney" , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Borislav Petkov , Dave Hansen , Eric Dumazet , Greg Kroah-Hartman , Ingo Molnar , Jann Horn , Jonathan Corbet , Kees Cook , Peter Zijlstra , Qian Cai , Thomas Gleixner , Will Deacon , "the arch/x86 maintainers" , "open list:DOCUMENTATION" , LKML , kasan-dev , Linux ARM , Linux-MM Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 27689180868D1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 Mon, Sep 7, 2020 at 3:41 PM Marco Elver wrote: > > From: Alexander Potapenko > > We make KFENCE compatible with KASAN for testing KFENCE itself. In > particular, KASAN helps to catch any potential corruptions to KFENCE > state, or other corruptions that may be a result of freepointer > corruptions in the main allocators. > > To indicate that the combination of the two is generally discouraged, > CONFIG_EXPERT=y should be set. It also gives us the nice property that > KFENCE will be build-tested by allyesconfig builds. > > Co-developed-by: Marco Elver > Signed-off-by: Marco Elver > Signed-off-by: Alexander Potapenko > --- > lib/Kconfig.kfence | 2 +- > mm/kasan/common.c | 7 +++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence > index 7ac91162edb0..b080e49e15d4 100644 > --- a/lib/Kconfig.kfence > +++ b/lib/Kconfig.kfence > @@ -10,7 +10,7 @@ config HAVE_ARCH_KFENCE_STATIC_POOL > > menuconfig KFENCE > bool "KFENCE: low-overhead sampling-based memory safety error detector" > - depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB) > + depends on HAVE_ARCH_KFENCE && (!KASAN || EXPERT) && (SLAB || SLUB) > depends on JUMP_LABEL # To ensure performance, require jump labels > select STACKTRACE > help > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 950fd372a07e..f5c49f0fdeff 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -18,6 +18,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -396,6 +397,9 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > tagged_object = object; > object = reset_tag(object); > > + if (is_kfence_address(object)) > + return false; Is this needed? At least in the slab patch I see that we do : if (kfence_free(objp)) { kmemleak_free_recursive(objp, cachep->flags); return; } before: /* Put the object into the quarantine, don't touch it for now. */ /* Put the object into the quarantine, don't touch it for now. */ if (kasan_slab_free(cachep, objp, _RET_IP_)) if (kasan_slab_free(cachep, objp, _RET_IP_)) return; return; If it's not supposed to be triggered, it can make sense to replace with BUG/WARN. > if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) != > object)) { > kasan_report_invalid_free(tagged_object, ip); > @@ -444,6 +448,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > if (unlikely(object == NULL)) > return NULL; > > + if (is_kfence_address(object)) > + return (void *)object; > + > redzone_start = round_up((unsigned long)(object + size), > KASAN_SHADOW_SCALE_SIZE); > redzone_end = round_up((unsigned long)object + cache->object_size, > -- > 2.28.0.526.ge36021eeef-goog >