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 0E3AAC433E0 for ; Sun, 24 Jan 2021 05:02:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC43A22CB2 for ; Sun, 24 Jan 2021 05:02:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726086AbhAXFC2 (ORCPT ); Sun, 24 Jan 2021 00:02:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:47220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726038AbhAXFC0 (ORCPT ); Sun, 24 Jan 2021 00:02:26 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D3BB822CB9; Sun, 24 Jan 2021 05:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1611464486; bh=4YYVNreWmm+F6m/SNONR+q8zmV8sjbqxEwGAHqEeXuw=; h=Date:From:To:Subject:In-Reply-To:From; b=jy8IoFyDsfdhnoqTpf3ipjhE/o4gYS3SoetQ6LKsXXwyhfH29AmK5TOR7VhJIgLdA yidF7g699p6wj8pg4e7mFReZowFUUwV1Or33ZwpDhf9/E2Uni7tBhoRWhr1hP4nwzI xa/QCylHcjy3ZM2aQP6bQWSgR0uFH18TNF9SdtVE= Date: Sat, 23 Jan 2021 21:01:25 -0800 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, aryabinin@virtuozzo.com, dan.j.williams@intel.com, dvyukov@google.com, glider@google.com, lecopzer.chen@mediatek.com, lecopzer@gmail.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, yj.chiang@mediatek.com Subject: [patch 07/19] kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow Message-ID: <20210124050125.TPTFvoKBt%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: Lecopzer Chen Subject: kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow During testing kasan_populate_early_shadow and kasan_remove_zero_shadow, if the shadow start and end address in kasan_remove_zero_shadow() is not aligned to PMD_SIZE, the remain unaligned PTE won't be removed. In the test case for kasan_remove_zero_shadow(): shadow_start: 0xffffffb802000000, shadow end: 0xffffffbfbe000000 3-level page table: PUD_SIZE: 0x40000000 PMD_SIZE: 0x200000 PAGE_SIZE: 4K 0xffffffbf80000000 ~ 0xffffffbfbdf80000 will not be removed because in kasan_remove_pud_table(), kasan_pmd_table(*pud) is true but the next address is 0xffffffbfbdf80000 which is not aligned to PUD_SIZE. In the correct condition, this should fallback to the next level kasan_remove_pmd_table() but the condition flow always continue to skip the unaligned part. Fix by correcting the condition when next and addr are neither aligned. Link: https://lkml.kernel.org/r/20210103135621.83129-1-lecopzer@gmail.com Fixes: 0207df4fa1a86 ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN") Signed-off-by: Lecopzer Chen Cc: Andrey Ryabinin Cc: Dan Williams Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: YJ Chiang Cc: Andrey Konovalov Signed-off-by: Andrew Morton --- mm/kasan/init.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) --- a/mm/kasan/init.c~kasan-fix-unaligned-address-is-unhandled-in-kasan_remove_zero_shadow +++ a/mm/kasan/init.c @@ -373,9 +373,10 @@ static void kasan_remove_pmd_table(pmd_t if (kasan_pte_table(*pmd)) { if (IS_ALIGNED(addr, PMD_SIZE) && - IS_ALIGNED(next, PMD_SIZE)) + IS_ALIGNED(next, PMD_SIZE)) { pmd_clear(pmd); - continue; + continue; + } } pte = pte_offset_kernel(pmd, addr); kasan_remove_pte_table(pte, addr, next); @@ -398,9 +399,10 @@ static void kasan_remove_pud_table(pud_t if (kasan_pmd_table(*pud)) { if (IS_ALIGNED(addr, PUD_SIZE) && - IS_ALIGNED(next, PUD_SIZE)) + IS_ALIGNED(next, PUD_SIZE)) { pud_clear(pud); - continue; + continue; + } } pmd = pmd_offset(pud, addr); pmd_base = pmd_offset(pud, 0); @@ -424,9 +426,10 @@ static void kasan_remove_p4d_table(p4d_t if (kasan_pud_table(*p4d)) { if (IS_ALIGNED(addr, P4D_SIZE) && - IS_ALIGNED(next, P4D_SIZE)) + IS_ALIGNED(next, P4D_SIZE)) { p4d_clear(p4d); - continue; + continue; + } } pud = pud_offset(p4d, addr); kasan_remove_pud_table(pud, addr, next); @@ -457,9 +460,10 @@ void kasan_remove_zero_shadow(void *star if (kasan_p4d_table(*pgd)) { if (IS_ALIGNED(addr, PGDIR_SIZE) && - IS_ALIGNED(next, PGDIR_SIZE)) + IS_ALIGNED(next, PGDIR_SIZE)) { pgd_clear(pgd); - continue; + continue; + } } p4d = p4d_offset(pgd, addr); _