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 886864F85CC; Mon, 19 Oct 2026 13:52:47 +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=1792417968; cv=none; b=AVjQ+S7Irk8gClLrdmM4nmhk1t7ppNyidbttVbjcl4ZPyYMdeh0cn/IzIol5HVdRVuhSAMpu6nIC8iTZ27p0b8rHnYkT9PgkVypnQKDmg2Q30SoxTNm74ZZGF8rdXNTx4Sk3v0OeSOUUFEvc6LK6FcFo2lCC67ZjF6pYE+Qxwzg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792417968; c=relaxed/simple; bh=UZd3+7Sz2K2tpPdVqkzPg7GAIgTpN7PEKpeBlkHrT3w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=U1/qUdyZphGwHPKwiEKEFXIcRjdr2mMZ+bdOmmLBWgUPBbDMj5+KtxAihHQQRjZsWrAaqZLfZIENDCTI8q+VUYMbb2kQ0v7jDl6e1vZJ4MyUdm0wtCLUGGlR9N2GzUkj0eT97NtpW6iPz7vOr7D6fQ/WNrLka/cRlrp9nL0YYAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=l7EUbFqc; 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="l7EUbFqc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AFB81F000C4; Mon, 19 Oct 2026 13:52:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792417967; bh=l9bSlYKhNusONtpe/ntZh5k1VKWpXkJkxTvQbX0UK3o=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=l7EUbFqcyWm4e7ptbtN/i/L9m+cg/xSsSWjxJKMp4HYTOz1CTTDXWrEWfY9urWcPg M9WI5LgV0DlHaEO4zwOI4P6ZH8Xx20yMLp2LOBuGK9a4dQWQ4wL6/Ukwt2sXLtKv6B qKrw7/L6NdyQG0xZV9+yTu0L5RCu6aYrZjp5EZp2/6jAGnWCt467KM/EZE6foMP+IF JZXG6FEwSDgWmzMPaVIJws9GHR2Gj9NKhjmuT/xJAiKfbYj+odGxnXbIREkul3oGiR zbhoR3T3qyJtlsHG/VeV2QNGMeSYjziuFAPqeoboffglVFS2+B0MUhAG8T8SLjjA/f StZ9hW6niwUQQ== Date: Mon, 19 Oct 2026 16:52:37 +0300 From: Mike Rapoport To: "Ning, Hongyu" Cc: x86@kernel.org, shuah@kernel.org, rick.p.edgecombe@intel.com, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, ljs@kernel.org, akpm@linux-foundation.org, david@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, hongyu.ning@intel.com, jolsa@kernel.org, dwindsor@gmail.com Subject: Re: [PATCH] selftests/x86: Fix userfaultfd test for shadow stack rejection Message-ID: References: <3b3e0a35-e664-40ab-84ad-afa3e31e3aea@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3b3e0a35-e664-40ab-84ad-afa3e31e3aea@linux.intel.com> On Mon, Oct 19, 2026 at 09:03:12AM +0800, Ning, Hongyu wrote: > Commit 3c58f641e813 ("userfaultfd: prevent registration of special > VMAs") prevents userfaultfd registration on shadow stack VMAs to avoid > bypassing shadow stack protections through UFFDIO_COPY. > > The existing shadow stack selftest still expects UFFDIO_REGISTER to > succeed and uses UFFDIO_COPY to populate the shadow stack. This causes > the selftest to fail on Kernels containing this security fix. > > Update the selftest to verify that UFFDIO_REGISTER rejects shadow stack > VMAs with EINVAL. Remove the obsolete userfaultfd fault handling thread > and UFFDIO_COPY test path. > > Tested on: Intel shadow stack capable x86_64 platform > > Before fix: > [FAIL] Userfaultfd test with return code 1 > > After fix: > [OK] Userfaultfd rejects shadow stack registration (EINVAL) > > Fixes: 3c58f641e813 ("userfaultfd: prevent registration of special VMAs") > > Signed-off-by: Hongyu Ning Acked-by: Mike Rapoport (Microsoft) > ChatGPT was used to assist with root-cause analysis and patch > preparation. The changes were reviewed and validated on Intel shadow > stack capable x86_64 platform, with all 12 shadow stack tests passing. > --- > .../testing/selftests/x86/test_shadow_stack.c | 105 ++++++------------ > 1 file changed, 34 insertions(+), 71 deletions(-) -- Sincerely yours, Mike.