From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793732753; b=JiihUpa5P3V9zWFLrgKdtftc7EspZhRKL4OXZpMjExKEzv3pMmpWUkkU9kBTS7iCIgTT imjbwoMLZbgJ+Ox+5iuWidmPNLta7n5TO3ZPtOLA5ImnUc9lgE4oh3jeoLGBNo+HweZXG k+eN47V6YW0kk4QnK/kqRBrD1ODCE1JK1gNsrKYtexvhj+jn5G/OxJeN1sc2DcYDjsQ9p VAuKmvtK5T8PVqjxLaqKBtqYqzGfLYtdQyPd042/v9KHMtAMWFaBvOGU99azTVbUUAhNf J1x9NERDsuVTI0c+gKYjdAe850pfEUQJS7M4gQiQD3uP5ZcIskGRJTtxsdnhBOYSmDw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793732753; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=HeJNsa6cJ6QNpsjilhgs8PG10NtpxUmbMSyIykHPOow=; b=nyfeQpaML0jB67pgDKfc7zfWmsonOr+YMRaX35AZefd+/j3oJe4nDZKlh6b+Sgd1uEJ1 D82O0o8VMaat0Ktmh7n/8c9TXWoWqJ0dMwZ/mZcTx8bLofWdCsV02H5NcF7c0G5Ttbomz vNYjx4DP7scjZgeeD5wowkeqRbzvvcEf7LBIX+f21sUv6md9wKtEGHAdNNv4SFJOpZAgK p4Zt2RxudNs7Ug6gtZmpC10OkYcOWyY3nYT2bJhsNlpZ4uXKOPAJLxlwTeaXatyeCr5ag 2RvBWRTmWvt25lr6dtsFsMvYcSl9p8Dc+3AzbdjUeG8wRVrlzq/TecinTBmxB8EEdgA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Tm2Ms7AR; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A24FA606A31B; Tue, 3 Nov 2026 19:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Tm2Ms7AR Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF4671F000C1; Tue, 3 Nov 2026 19:05:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793732753; bh=HeJNsa6cJ6QNpsjilhgs8PG10NtpxUmbMSyIykHPOow=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Tm2Ms7ARRWfmr8ayv6N+1djm7L5xFdCVSz8tSi2mTXHAowcCDGbvK/lDyvmEqybsd YfDAVqXOvWa4BDymDjqjfclHOqtSr8ymzmt/0+WPxd2iF7sJ7/p3FXEjFN8WVgKilX i5Iiv2pQfvys9YvlFvxuZ1GCEyDMpBJqr8P3hSl17H4Frg1xvFViFFe0dCySAvB50L oUnoQyhIS1hdArWYWvLM8NYL+liPREMfvy6as1ttb2ndB2mzCduEvcwdrzYk21GksW gjlNL7ArZ32XovBSVOh8Ce4gWgYE1fqxdDx77occRhf9rMxbebHhcEQV9rZYSugPPx 4RNHVFB4PRPsA== Date: Tue, 3 Nov 2026 21:05:46 +0200 From: Mike Rapoport To: Umang Pokhriyal Cc: Andrew Morton , Peter Xu , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] selftests/mm: test a uffd write-protect range with an unregistered page Message-ID: References: <20261102103621.156928-1-umangpokhriyall@gmail.com> <20261102103621.156928-3-umangpokhriyall@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261102103621.156928-3-umangpokhriyall@gmail.com> Hi Umang, On Mon, Nov 02, 2026 at 04:06:21PM +0530, Umang Pokhriyal wrote: > Register only the first of two pages and check that UFFDIO_WRITEPROTECT > over both pages fails with ENOENT without changing the first page, when > protecting and when unprotecting. I don't think it's worth keeping the test for a regression we already fixed. > Signed-off-by: Umang Pokhriyal > --- > tools/testing/selftests/mm/uffd-unit-tests.c | 56 ++++++++++++++++++++ > 1 file changed, 56 insertions(+) > > diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c > index 298609544..57e442fd2 100644 > --- a/tools/testing/selftests/mm/uffd-unit-tests.c > +++ b/tools/testing/selftests/mm/uffd-unit-tests.c > @@ -375,6 +375,56 @@ static void uffd_wp_unpopulated_test(uffd_global_test_opts_t *gopts, uffd_test_a > uffd_test_pass(); > } > > +/* > + * UFFDIO_WRITEPROTECT over a range whose second page is not registered must > + * fail without changing the first page, in both directions. > + */ > +static void uffd_wp_partial_range_test(uffd_global_test_opts_t *gopts, > + uffd_test_args_t *args) > +{ > + struct uffdio_writeprotect prms = { > + .range.start = (uint64_t)gopts->area_dst, > + .range.len = 2 * gopts->page_size, > + }; > + uint64_t value; > + int pagemap_fd; > + > + /* Only the first page is registered; the second is a separate VMA */ > + if (uffd_register(gopts->uffd, gopts->area_dst, gopts->page_size, > + false, true, false)) > + err("register failed"); > + > + pagemap_fd = pagemap_open(); > + *gopts->area_dst = 1; > + > + prms.mode = UFFDIO_WRITEPROTECT_MODE_WP; > + if (!ioctl(gopts->uffd, UFFDIO_WRITEPROTECT, &prms) || errno != ENOENT) { > + uffd_test_fail("protect over an unregistered page did not fail with ENOENT"); > + goto out; > + } > + value = pagemap_get_entry(pagemap_fd, gopts->area_dst); > + if (value & PM_UFFD_WP) { > + uffd_test_fail("failed protect changed the first page"); > + goto out; > + } > + > + wp_range(gopts->uffd, (uint64_t)gopts->area_dst, gopts->page_size, true); > + prms.mode = 0; > + if (!ioctl(gopts->uffd, UFFDIO_WRITEPROTECT, &prms) || errno != ENOENT) { > + uffd_test_fail("unprotect over an unregistered page did not fail with ENOENT"); > + goto out; > + } > + value = pagemap_get_entry(pagemap_fd, gopts->area_dst); > + if (!(value & PM_UFFD_WP)) { > + uffd_test_fail("failed unprotect changed the first page"); > + goto out; > + } > + > + uffd_test_pass(); > +out: > + close(pagemap_fd); > +} > + > static void uffd_wp_fork_test_common(uffd_global_test_opts_t *gopts, uffd_test_args_t *args, > bool with_event) > { > @@ -2403,6 +2453,12 @@ uffd_test_case_t uffd_tests[] = { > .uffd_feature_required = > UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_UNPOPULATED, > }, > + { > + .name = "wp-partial-range", > + .uffd_fn = uffd_wp_partial_range_test, > + .mem_targets = MEM_ANON, > + .uffd_feature_required = UFFD_FEATURE_PAGEFAULT_FLAG_WP, > + }, > { > .name = "minor", > .uffd_fn = uffd_minor_test, > -- > 2.53.0 > -- Sincerely yours, Mike.