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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B5C00CD5BCF for ; Thu, 13 Nov 2025 11:42:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 01C848E000A; Thu, 13 Nov 2025 06:42:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F35FD8E0002; Thu, 13 Nov 2025 06:42:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E73098E000A; Thu, 13 Nov 2025 06:42:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id D65DE8E0002 for ; Thu, 13 Nov 2025 06:42:16 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7BEBC140941 for ; Thu, 13 Nov 2025 11:42:16 +0000 (UTC) X-FDA: 84105395472.21.55FAAE8 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf18.hostedemail.com (Postfix) with ESMTP id EAFA71C0004 for ; Thu, 13 Nov 2025 11:42:14 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=VU146KzH; spf=pass (imf18.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1763034134; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=d5BQEnTGDYort28gv5F5zQxkt5w5KrhNkvYO5PsZPTs=; b=q2zojKc83i/5fBUeWKau7jH3vCpqDHs0fNAoZOM0kdpDkujhwPQTV90KIckyUKTkiZwKcf xDFwRdPVpYCcsEmWhbgFat3oZvBz4fL+XO65LQ7qM+7rSmnVt7ybjwkLPffscFwedMMcul zCzK11Mri+ZRQXCi5lZ4fof7qwX8fho= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763034134; a=rsa-sha256; cv=none; b=tqsWR22qqtlSrdPIapZjPKDmZg4ZFctiZQCWBhgoYrEe5jFXsHE2/fZdCwGuZnhjkaiA9S rVYYoz9k0Xj2cTjvd4hTyA4Kej44mRbTowxIxQJrfpytWABWCiktzkv7QcGiQmKp3R2hHy 8b5uZ/C176WZ767yZtY8DAeuCIuihIU= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=VU146KzH; spf=pass (imf18.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 57A33601B9; Thu, 13 Nov 2025 11:42:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC98CC4AF09; Thu, 13 Nov 2025 11:42:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763034134; bh=STrLN9TaMedzhy/AV3DPEXhd1qFmA8sZ1GjlOFXHjO4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VU146KzHCHjuBsPUsgTIzQH0cXL+9V8Z6BJqbMtO79x84t7yUlDckcL2h7qf9bRFg obF3uDlCXmobGcjhbUpr3Wa7VgZ6PIAjSBYOzjxqEbNq9uGJvWb8yDvfj08/PQ/g6a D13+Zzxmn8YrUz2QFj168p5x6HYuAqYEW1zTQ3zSxxfbU4fE2KkhZKF5gYoWk1cLlw MTsxXNGTVAzosrfZAxLZ83pNPnN8uj3mBnqlX8pye1ZjQHW1YlAcQHdvIY6394FQSB 1aQEUiLoVhEL9j6cYVFgedr30vAUY4djX/mqiBY0rzyeqOfTiityRADnFo5V5M65hg pEb7zGtClVyQA== Date: Thu, 13 Nov 2025 13:42:04 +0200 From: Mike Rapoport To: Carlos Llamas Cc: Andrew Morton , Peter Xu , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Ujwal Kundur , Brendan Jackman , kernel-team@android.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "open list:MEMORY MANAGEMENT - USERFAULTFD" , "open list:KERNEL SELFTEST FRAMEWORK" Subject: Re: [PATCH] selftests/mm: fix division-by-zero in uffd-unit-tests Message-ID: References: <20251113034623.3127012-1-cmllamas@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251113034623.3127012-1-cmllamas@google.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: EAFA71C0004 X-Stat-Signature: djbjgx7h9seeqi5aebqzfcarjdb3pnzj X-Rspam-User: X-HE-Tag: 1763034134-825884 X-HE-Meta: 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 BkQ19fxl bzyxh51715VDqvq+1BZRFqet3A29Uq4H1farJURFasid32/pvIzXZGrLqW/rd3tg1AEZcIpwUJNlQII1yA+f+arh5a23K/VRIdqytPiu38fqdrXgugLzpZfSL9aAtmL8vk5IXs5u+SiAOLAr8szbjQmOKZn2X78OFvnxtAdu/cxO4ykKVVSld73dYKfInX24CgSPsemOyNXrx57FkKEK8BkGSuQ3xN27KE1x653thOIR09mq/SYf2eXIeLwt/EHJOvsMtIX71K8axlIMeu8rEsEhGwKnt0xurkaWXxMWZq/4C8uFqb+bNeU8PQTeksih880MZnj84lUo45potipMlc2S9mySBWbxoXCOpUzU8XSAOuSzTHe4dAXXIXQ== 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: List-Subscribe: List-Unsubscribe: On Thu, Nov 13, 2025 at 03:46:22AM +0000, Carlos Llamas wrote: > Commit 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global > vars into struct") moved some of the operations previously implemented > in uffd_setup_environment() earlier in the main test loop. > > The calculation of nr_pages, which involves a division by page_size, now > occurs before checking that default_huge_page_size() returns a non-zero > This leads to a division-by-zero error on systems with !CONFIG_HUGETLB. > > Fix this by relocating the non-zero page_size check before the nr_pages > calculation, as it was originally implemented. > > Cc: stable@vger.kernel.org > Fixes: 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global vars into struct") > Signed-off-by: Carlos Llamas Agree with what David and Lorenzo said about cc:stable. Reviewed-by: Mike Rapoport (Microsoft) > --- > tools/testing/selftests/mm/uffd-unit-tests.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c > index 9e3be2ee7f1b..f917b4c4c943 100644 > --- a/tools/testing/selftests/mm/uffd-unit-tests.c > +++ b/tools/testing/selftests/mm/uffd-unit-tests.c > @@ -1758,10 +1758,15 @@ int main(int argc, char *argv[]) > uffd_test_ops = mem_type->mem_ops; > uffd_test_case_ops = test->test_case_ops; > > - if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) > + if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) { > gopts.page_size = default_huge_page_size(); > - else > + if (gopts.page_size == 0) { > + uffd_test_skip("huge page size is 0, feature missing?"); > + continue; > + } > + } else { > gopts.page_size = psize(); > + } > > /* Ensure we have at least 2 pages */ > gopts.nr_pages = MAX(UFFD_TEST_MEM_SIZE, gopts.page_size * 2) > @@ -1776,12 +1781,6 @@ int main(int argc, char *argv[]) > continue; > > uffd_test_start("%s on %s", test->name, mem_type->name); > - if ((mem_type->mem_flag == MEM_HUGETLB || > - mem_type->mem_flag == MEM_HUGETLB_PRIVATE) && > - (default_huge_page_size() == 0)) { > - uffd_test_skip("huge page size is 0, feature missing?"); > - continue; > - } > if (!uffd_feature_supported(test)) { > uffd_test_skip("feature missing"); > continue; > -- > 2.51.2.1041.gc1ab5b90ca-goog > -- Sincerely yours, Mike.