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 2E9CE382F2F; Sun, 6 Sep 2026 18:12:53 +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=1788718374; cv=none; b=tCtF1EJMSKdmSrAcwdxTdclyj5OhkSc5YrOAnjnYodLup0ALx1DnQTMtNh7fhndGxDVk+EXRqz1PNXSx9QqeBuXbP9kYkGR4MLx+U6II8pGxTrkeKtzYvySW1fM/2sYuzvriIHRjeTUIEgMUEXsP4gUUzjEFT8Zdke3Ej+LFX0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788718374; c=relaxed/simple; bh=zRGTPvX5kJiSubiY55rrWNV2xl5Y77Rfc3wQHRNVRgg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qJn+F5AbELRm11uGb1eBd3ChwQwm/O/NSa3wT4wpuD4Ltm5wfXyvEbNwNNmnkAa5pX8K9r7rgDUi5ewOraVWd9VzyJ5w6+XZoiL5o5RsLEbHS16q7cU6pzW2A3rBUKR3DICavuziV/3DzHYaT3eYukL47Kav48ClOmzordgRIQU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jsELhNFQ; 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="jsELhNFQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68FA11F00A3A; Sun, 6 Sep 2026 18:12:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788718373; bh=0UKbj6KtD1AbJpXqfcrRDmxZiWxq+JT8NwXXeqVCxlw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=jsELhNFQUdpiI6ljiNDCByAj0a2uc2qEJz4YOwrpLYssH1qreJPwV3XOZCVHLxb1Y omSwTBCNzuTETNBxaL3nvQngjyX8o5lkXZBozmwQwHPqY3JWWNjtDdtFCrodjiNA6K E8wbFxkkZz+ZzPxHaKDODWaebmO3YJil3IDcSAqGnrNREe3JOsYct+u7Vhh1PGq3WO 0D2uQnxWMHkrDNyDV1K3t18VmmI6ScSY4nbypN8VnEZfifXPP+OQXifrJJsaFhnj/P 2RjeBqssjhnAgRSTOujABdUiqeIaLPyz+UR/zz/0qqHoPYUyjABPl76RcMZXmW+u44 FPECu5yTYvuCw== Date: Sun, 6 Sep 2026 11:12:47 -0700 From: Nathan Chancellor To: Dave Hansen Cc: Mike Rapoport , Dave Hansen , linux-tip-commits@vger.kernel.org, Juergen Gross , "Lorenzo Stoakes (ARM)" , syzbot@syzkaller.appspotmail.com, Atish Patra , Nikunj A Dadhania , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: [tip: x86/urgent] x86/mm/pat: Fix effective RW computation in lookup_address_in_pgd_attr() Message-ID: <20260906181247.GA1148584@ax162> References: <20260813-cpa-fixes-v2-5-39b4ff90f91d@kernel.org> <178837401172.3717435.314324339347590321.tip-bot2@tip-bot2> <20260905044253.GA3816371@ax162> 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: On Sun, Sep 06, 2026 at 07:50:26AM -0700, Dave Hansen wrote: > On 9/4/26 21:42, Nathan Chancellor wrote: > > I just bisected the following warning on a couple of my test machines to > > commit 453e78594434 ("x86/mm/pat: Fix effective RW computation in > > lookup_address_in_pgd_attr()") in next-20260904. > ... > > If there is any information I can provide to help debug this, I am happy > > to provide it. > > Well, the thing you bisected to is the patch that fixes the warning. The Hmmm, I don't see a warning prior to this patch though. Do you mean that this patch is just revealing the bad behavior that you mention below? > actual issue comes from: > > if (pages == &its_pages) > set_memory_x((unsigned long)page, 1); > > which its_alloc() does on an execmem allocation. Any chance you could > get the output of: > > /sys/kernel/debug/page_tables/current_kernel > > for the page that page that it's complaining about? I'm curious if this > is temporary or permanent. Sure. For CPA detected W^X violation: 8000000000000123 -> 0000000000000123 range: 0xffffffffc0200000 - 0xffffffffc0200fff PFN 100e00 I think it is this line if I understand correctly? 0xffffffffc0200000-0xffffffffc0400000 2M ro PSE GLB x pmd -- Cheers, Nathan