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 9325AC433E0 for ; Sun, 24 Jan 2021 05:02:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65C1322CB2 for ; Sun, 24 Jan 2021 05:02:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726092AbhAXFCp (ORCPT ); Sun, 24 Jan 2021 00:02:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:47284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726096AbhAXFCd (ORCPT ); Sun, 24 Jan 2021 00:02:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9A34522D37; Sun, 24 Jan 2021 05:01:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1611464506; bh=yKNN4Z5OscCqwPYjf8+qmsc/A/D8Skjewqd9GATmXlg=; h=Date:From:To:Subject:In-Reply-To:From; b=m9RponltuKB+Zwq+BDrDUQIhyC0fvQwQnX0h4wtXGNT3TlZ8+c9hn1Uou0BF5D0kl NTjWEA0xxDHIXa/LVBHTeGXZA41MWuV1nVUkxzzmNLNRoWI8WnvpOod9wO0R6o/xfj q2qvSL0M2wpugJvl54bq9jeji1JzrqSNJhZlNGvE= Date: Sat, 23 Jan 2021 21:01:43 -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, vincenzo.frascino@arm.com, will.deacon@arm.com Subject: [patch 11/19] kasan, mm: fix resetting page_alloc tags for HW_TAGS Message-ID: <20210124050143.UF-3I8lr9%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 resetting page_alloc tags for HW_TAGS A previous commit added resetting KASAN page tags to kernel_init_free_pages() to avoid false-positives due to accesses to metadata with the hardware tag-based mode. That commit did reset page tags before the metadata access, but didn't restore them after. As the result, KASAN fails to detect bad accesses to page_alloc allocations on some configurations. Fix this by recovering the tag after the metadata access. Link: https://lkml.kernel.org/r/02b5bcd692e912c27d484030f666b350ad7e4ae4.1611074450.git.andreyknvl@google.com Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata") Signed-off-by: Andrey Konovalov Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: Marco Elver Cc: Catalin Marinas Cc: Will Deacon Cc: Vincenzo Frascino Cc: Andrey Ryabinin Cc: Peter Collingbourne Cc: Evgenii Stepanov Cc: Branislav Rankov Cc: Kevin Brodsky Signed-off-by: Andrew Morton --- mm/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/page_alloc.c~kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags +++ a/mm/page_alloc.c @@ -1207,8 +1207,10 @@ static void kernel_init_free_pages(struc /* s390's use of memset() could override KASAN redzones. */ kasan_disable_current(); for (i = 0; i < numpages; i++) { + u8 tag = page_kasan_tag(page + i); page_kasan_tag_reset(page + i); clear_highpage(page + i); + page_kasan_tag_set(page + i, tag); } kasan_enable_current(); } _