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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED 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 5B942C433E0 for ; Sun, 24 Jan 2021 05:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33C7022CB9 for ; Sun, 24 Jan 2021 05:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726217AbhAXFCm (ORCPT ); Sun, 24 Jan 2021 00:02:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:47242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726056AbhAXFCd (ORCPT ); Sun, 24 Jan 2021 00:02:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8905F22D2C; Sun, 24 Jan 2021 05:01:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1611464501; bh=sh700x7Hu6vxNrBP4J9bML1JZ69fplcFrjgPi1lNSIc=; h=Date:From:To:Subject:In-Reply-To:From; b=pLOURBliCWTpM/V0kNtdFeaonQPu96t3IaXyxMJ1rkxPajuFq6BtERocScIv5gI00 Lxw+Kf2qdcsDF4gtpW4KxbdVUq3uzTkPNIUzoBKvxi7TvGRL1pBcIT5Yn+uATBChI5 FnYvKM0cz0r3JZ12DDz2Y2KLevY8l/L7yZqths2s= Date: Sat, 23 Jan 2021 21:01:38 -0800 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, aryabinin@virtuozzo.com, Branislav.Rankov@arm.com, catalin.marinas@arm.com, dvyukov@google.com, elver@google.com, eugenis@google.com, glider@google.com, kevin.brodsky@arm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, pcc@google.com, torvalds@linux-foundation.org, vbabka@suse.cz, vincenzo.frascino@arm.com, will.deacon@arm.com Subject: [patch 10/19] kasan, mm: fix conflicts with init_on_alloc/free Message-ID: <20210124050138.apmWliFQh%akpm@linux-foundation.org> In-Reply-To: <20210123210029.a7c704d0cab204683e41ad10@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Andrey Konovalov Subject: kasan, mm: fix conflicts with init_on_alloc/free A few places where SLUB accesses object's data or metadata were missed in a previous patch. This leads to false positives with hardware tag-based KASAN when bulk allocations are used with init_on_alloc/free. Fix the false-positives by resetting pointer tags during these accesses. (The kasan_reset_tag call is removed from slab_alloc_node, as it's added into maybe_wipe_obj_freeptr.) Link: https://linux-review.googlesource.com/id/I50dd32838a666e173fe06c3c5c766f2c36aae901 Link: https://lkml.kernel.org/r/093428b5d2ca8b507f4a79f92f9929b35f7fada7.1610731872.git.andreyknvl@google.com Fixes: aa1ef4d7b3f67 ("kasan, mm: reset tags when accessing metadata") Signed-off-by: Andrey Konovalov Reported-by: Dmitry Vyukov Acked-by: Vlastimil Babka Cc: Catalin Marinas Cc: Vincenzo Frascino Cc: Alexander Potapenko Cc: Marco Elver Cc: Will Deacon Cc: Andrey Ryabinin Cc: Peter Collingbourne Cc: Evgenii Stepanov Cc: Branislav Rankov Cc: Kevin Brodsky Signed-off-by: Andrew Morton --- mm/slub.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/mm/slub.c~kasan-mm-fix-conflicts-with-init_on_alloc-free +++ a/mm/slub.c @@ -2791,7 +2791,8 @@ static __always_inline void maybe_wipe_o void *obj) { if (unlikely(slab_want_init_on_free(s)) && obj) - memset((void *)((char *)obj + s->offset), 0, sizeof(void *)); + memset((void *)((char *)kasan_reset_tag(obj) + s->offset), + 0, sizeof(void *)); } /* @@ -2883,7 +2884,7 @@ redo: stat(s, ALLOC_FASTPATH); } - maybe_wipe_obj_freeptr(s, kasan_reset_tag(object)); + maybe_wipe_obj_freeptr(s, object); if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) memset(kasan_reset_tag(object), 0, s->object_size); @@ -3329,7 +3330,7 @@ int kmem_cache_alloc_bulk(struct kmem_ca int j; for (j = 0; j < i; j++) - memset(p[j], 0, s->object_size); + memset(kasan_reset_tag(p[j]), 0, s->object_size); } /* memcg and kmem_cache debug support */ _