Received: by 2002:a05:6a10:2726:0:0:0:0 with SMTP id ib38csp5236403pxb; Mon, 28 Mar 2022 09:47:18 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxjnNd5N0OwpAi9Y1+HRk2Bu1/cjcxMQI1L7td0nIKvucD/73TCtIJeLRgxN1x5Yl7aj0jt X-Received: by 2002:a05:6870:4412:b0:dd:a03a:75af with SMTP id u18-20020a056870441200b000dda03a75afmr26603oah.266.1648486038464; Mon, 28 Mar 2022 09:47:18 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1648486038; cv=none; d=google.com; s=arc-20160816; b=xpenfCOekX0QtF4duKYjAtCSvAMMOJbHJFNrlGOE0p6p8u5x57MfZYeVrPzO7UVKEp hj+Tik4Rx7/BuoypMH+DudHDLv4A9bmH0a0jOzYkg2q0IZTWYPZLCbH3LDXj9RwY2ToS bq16OWxqbSCouoqvP8vld/gFZqR73wSF7pstBN3ivnXeDMIZCH5gW/eCXi3EsPqaapXP 7eCD88td4LGsv3tMzrEQyblBoW0fCr4nSAjhWV+OiZswTquxzNQLOztz0a6FINDF4TM3 26TNd8gjuZBnWYSpdN5/jd3yZCZcgNqCoxBr8+kb5A6FYoH82s6RMbJ6exLDK4IYfMo7 z0gA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=0Ij7EScJudVOi5RYvphdBBCIR4h1LCA2MSSb6SklIMc=; b=q0XZQJHS3en+RYIAPUxMLBeze1hgCJPewWWyiYCB7oA5SoGRms2rJRvoo12gWJTYr5 z8n5t1QvfotZhs1eDRWGHLuo6AZy8DKLkuNRF/9gSjAfXo3VqFQgct0eVC2qWbC4430o MPMCh4levaDQUd9ACVUntwAlqDXEOrwW9JusorpT+XBXpf/gaD3uTcSLnGcOEFaVwXA3 SNMdsFGAk091mE1Z/tmcicNBl/2eEE+30fMxt23nGbhK6OYddkAYGfGI19c4Xieg5VOW Y3oQrPdE6nX630v0q8XsuqQRADRNo81jZbCSTWdMnwsutqIpwM92s294CVLOua4ERZ1s UoCA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=g9VuNeim; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id d1-20020a056830138100b005cb2fc13882si10280625otq.254.2022.03.28.09.47.04; Mon, 28 Mar 2022 09:47:18 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=g9VuNeim; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238959AbiC1Hwv (ORCPT + 99 others); Mon, 28 Mar 2022 03:52:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237327AbiC1Hwu (ORCPT ); Mon, 28 Mar 2022 03:52:50 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C13852E4F; Mon, 28 Mar 2022 00:51:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 3291ACE10D4; Mon, 28 Mar 2022 07:51:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D9CEC004DD; Mon, 28 Mar 2022 07:51:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648453867; bh=+JP5Ab1oWpqS8fzwyXV7SypqA8884zZbHeYFiDOUYbg=; h=From:To:Cc:Subject:Date:In-Reply-To:From; b=g9VuNeim6joiptQyzGGlTwbrBJQBHdctKG6oRM0jRe1VX0NJtCshIKkdWYVGjPZ4+ XXzzmE4Fzok/ffsHEJLyeqpKnFXxLftxIU/U78JmBqoSsW5plU9xnDOirD5Pq6jdTc 2u3YtpjgKL3p1uq2PWefOEmCvndNcIUEfA9i6JZEpJ6de1MFEQClXZL0fl+36O+v3d Rnr2SEcVbmirNVC4QGXeONOWn32wOesViauO0u5MatbM4A7qpcSUjIRVVTm7OdKz5j 7vkPuvKBjN6JiJSEgR6W8XGycvTod39XKTuHHITwEuUGmGIMjOKaHCY1ByBzWIW8hf Ea16OCChdMx0Q== From: sj@kernel.org To: Xiaomeng Tong Cc: sj@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] damon: vaddr-test: fix a missing check on list iterator Date: Mon, 28 Mar 2022 07:51:04 +0000 Message-Id: <20220328075104.31125-1-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220327080345.12295-1-xiam0nd.tong@gmail.com> X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Xiaomeng, On Sun, 27 Mar 2022 16:03:45 +0800 Xiaomeng Tong wrote: > The bug is here: > KUNIT_EXPECT_EQ(test, r->ar.start, start + i * expected_width); > KUNIT_EXPECT_EQ(test, r->ar.end, end); > > For the damon_for_each_region(), just like list_for_each_entry(), > the list iterator 'drm_crtc' will point to a bogus position > containing HEAD if the list is empty or no element is found. > This case must be checked before any use of the iterator, > otherwise it will lead to a invalid memory access. We ensure 'damon_va_evenly_split_region()' successes before executing the loop, so the issue cannot occur. That said, I think this patch makes code better to read. Could you please resend this patch after fixing the commit message? > > To fix this bug, just mov two KUNIT_EXPECT_EQ() into the loop s/mov/move > when found. > > Cc: stable@vger.kernel.org > Fixes: 044cd9750fe01 ("mm/damon/vaddr-test: split a test function having >1024 bytes frame size") > Signed-off-by: Xiaomeng Tong > --- > mm/damon/vaddr-test.h | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/damon/vaddr-test.h b/mm/damon/vaddr-test.h > index 6a1b9272ea12..98b7a9f54b35 100644 > --- a/mm/damon/vaddr-test.h > +++ b/mm/damon/vaddr-test.h > @@ -281,14 +281,16 @@ static void damon_test_split_evenly_succ(struct kunit *test, > KUNIT_EXPECT_EQ(test, damon_nr_regions(t), nr_pieces); As mentioned above, this will ensure the loop will not result in the bogus pointer problem. > > damon_for_each_region(r, t) { > - if (i == nr_pieces - 1) > + if (i == nr_pieces - 1) { > + KUNIT_EXPECT_EQ(test, > + r->ar.start, start + i * expected_width); > + KUNIT_EXPECT_EQ(test, r->ar.end, end); > break; > + } > KUNIT_EXPECT_EQ(test, > r->ar.start, start + i++ * expected_width); > KUNIT_EXPECT_EQ(test, r->ar.end, start + i * expected_width); > } > - KUNIT_EXPECT_EQ(test, r->ar.start, start + i * expected_width); > - KUNIT_EXPECT_EQ(test, r->ar.end, end); > damon_free_target(t); > } > > -- > 2.17.1 > > Thanks, SJ