From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F6AB4848AA; Mon, 28 Sep 2026 09:11:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790586719; cv=none; b=YuXXpvDKniLUs+lAl0SIMoB0lK86AFv72qnS8tWAx/J1u9c9teZE5vMGsOp6nI6h9cNeTkxrghdGWUfsvAsZPp25/Z4OxoKaW5Fe6OHdoxJKJ/J9S9iWGQ5uxTC90FuPAtxiclyeMlT2dgCSegUO40sYPvbGBE25KSFzENAKIQQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790586719; c=relaxed/simple; bh=LruxEbhmF6IGdxuRygoRSb1UZhzzw1t+jcqvjEZErcE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=O3Es0t9jUt+jMcoBaDcsK+6uTfUewvvJGA5OfkHIXC/9BeMgft9Jznxi6zuu9A7Fez+pC1e9DOhyMFzct7wV+Dn094MU7cRXQu47UkU01MDl7XYeaCqn3rihVVTPOy2axfhCQjLuUDPorDqIGJ3Cr0JTf5nsqBJ3fMEBVolSuFY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fU8GXNtN; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fU8GXNtN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1691D1F00893; Mon, 28 Sep 2026 09:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790586718; bh=05NX/KueojKbo1FusJ/pQWHXEPJws9b0LGfxeblMA/U=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=fU8GXNtNeuPrs802+rjWChGkvfufVE4OLG5EwtQwcuenhC6m8FhzlFRr8MwKJEnvK MANc9vUSA2xGzmnHx3AzxE0AHBFdHi+X3tzkwuSeLIY534ly4y09dL5up8EPY58MO2 gHDGUl3fT21h6W9c0xaCoCEXu7iC0sfuprPdMHfec7HSZygKWioZawZfdOsb6zIRR5 4RnF3Qh83zb6BPRTMNdp+5A1UXcQw3k6ePLq0fZfUHeYS0am8F4bqWg2tuQy5SBeB7 5tX927u56A75jbpXnycES5HhLo+41TES7GpZF4NP79CYNq/M2eEQm8ZbicAus3zifB JISbXt0JFnDnQ== Message-ID: Date: Mon, 28 Sep 2026 11:11:50 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] selftests/mm: add tests for UFFDIO_MOVE of a uffd-protected swap entry To: Donggeun Yoo , akpm@linux-foundation.org, rppt@kernel.org Cc: peterx@redhat.com, surenb@google.com, aarcange@redhat.com, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, mhocko@suse.com, shuah@kernel.org, kirill@shutemov.name, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260926124145.2878520-1-donggeunyoo.kernel@gmail.com> <20260926124145.2878520-3-donggeunyoo.kernel@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/26/26 14:41, Donggeun Yoo wrote: > Move a swapped-out page out of a write-protected or RWP-protected area into > a destination registered for missing faults only, and read pagemap bit 57 > at the destination. The destination was never protected, so the bit must > be clear. > > Assisted-by: LLM > Signed-off-by: Donggeun Yoo > --- > tools/testing/selftests/mm/uffd-unit-tests.c | 84 ++++++++++++++++++++ > 1 file changed, 84 insertions(+) > > diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c > index ef9b3956bdcfd..580178630eded 100644 > --- a/tools/testing/selftests/mm/uffd-unit-tests.c > +++ b/tools/testing/selftests/mm/uffd-unit-tests.c > @@ -2037,6 +2037,75 @@ static void uffd_move_pmd_split_test(uffd_global_test_opts_t *gopts, uffd_test_a > uffd_move_pmd_handle_fault); > } > > +/* > + * Moving a swapped-out page out of a write-protected or RWP-protected area > + * must not carry the uffd bit into a destination registered for missing > + * faults only: such a bit is never cleared afterwards, so pagemap keeps > + * reporting the page as uffd-tracked. > + * > + * Needs a swap device; skipped if MADV_PAGEOUT cannot evict the page. > + */ > +static void uffd_move_swap_test_common(uffd_global_test_opts_t *gopts, > + bool rwp) > +{ > + unsigned long page_size = gopts->page_size; > + struct uffdio_move move = { }; > + int pagemap_fd; > + > + if (rwp) { > + if (uffd_register_rwp(gopts->uffd, gopts->area_src, page_size)) > + err("register src failure"); > + } else if (uffd_register(gopts->uffd, gopts->area_src, page_size, > + false, true, false)) { > + err("register src failure"); > + } Why not combine it with the protection? if (rwp) { if (uffd_register_rwp(gopts->uffd, gopts->area_src, page_size)) err("register src failure"); rwprotect_range(gopts->uffd, (unsigned long)gopts->area_src, page_size, true); } else { if (uffd_register(gopts->uffd, gopts->area_src, page_size, false, true, false)) err("register src failure"); wp_range(gopts->uffd, (unsigned long)gopts->area_src, page_size, true); } > + if (uffd_register(gopts->uffd, gopts->area_dst, page_size, > + true, false, false)) > + err("register dst failure"); > + > + if (rwp) > + rwprotect_range(gopts->uffd, (unsigned long)gopts->area_src, > + page_size, true); > + else > + wp_range(gopts->uffd, (unsigned long)gopts->area_src, > + page_size, true); > + > + pagemap_fd = pagemap_open(); Why not do that at the very top? int pagemap_fd = pagemap_open(); > + if (madvise(gopts->area_src, page_size, MADV_PAGEOUT)) > + err("MADV_PAGEOUT"); > + if (!pagemap_is_swapped(pagemap_fd, gopts->area_src)) { > + uffd_test_skip("MADV_PAGEOUT did not swap the page; is swap enabled?"); > + goto out; > + } > + > + move.dst = (unsigned long)gopts->area_dst; > + move.src = (unsigned long)gopts->area_src; > + move.len = page_size; You can set that all already when initializing aboce struct uffdio_move move = { .dst = (unsigned long)gopts->area_dst, [...] }; > + if (ioctl(gopts->uffd, UFFDIO_MOVE, &move)) > + err("UFFDIO_MOVE"); BTW, why do we fail the entire test here instead of only this test case? -- Cheers, David