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 937143749F7 for ; Sat, 4 Jul 2026 02:05:48 +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=1783130749; cv=none; b=d2/3X/Hsc7c6NwYJPBNBAVo2qaSyIoMBZWAwP1mzgzhxt6FKZzJYBrSGdJCzGCx8lF+cZ4NZoKmddEPvREYUzsrxTOZfpLy3An0R1nUPBcQaq01L1Qi0IwV6WZyU2WVfF27es0fy8i/bdAJ8b4shs1EUXHEspxfy43xbKHJmQuY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783130749; c=relaxed/simple; bh=p2esmnv3C4tAtf/2wdWCj8HNGs/JBx9foPru6p5TLGQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aTv1BfXUe1w6tbJQ/oB8CuV7TezCuUPzZ6w6BoeJ24aTIMqq9pPagHZWd8109yotL3ah+pKvLPc8LcZ6fvQzwANI1EPUXoSDAb4nAQv3RiM2R3rcC/7yew7EZ9rzuAYoyPYbhDF6YqGT2dIL6wpDSl/4rwA2jo615iEDCb1MGss= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jz7SoV2m; 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="jz7SoV2m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 181AE1F000E9; Sat, 4 Jul 2026 02:05:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783130748; bh=81PCE2mbwOgj8kX6gc2Z2Hk9aUjJ1uNYjYVBkzh6qwI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jz7SoV2mbK0kkcDiWeKLz8bS1DcTwg2TeBQ4JS4OJku37uVDxMqwXX3qzFnKAgUgi oTROFkTDTswR2CeoZHrBTRzEcS6oguuQGmLJpQjGML1ZXtHBY9n3Kt6g/Tioaj1OlJ VD2Ff7DCImAOtWyJGCJi3MfXhL/pfaqus6dG6bCwheIVvRWnAYeJw0jDfzcdQ3y7wf FS6TvA5nTF75k7VnLiMV5HUBtqtrunbSnUFkOh2Smzl9HaAcDcgCb+KtEpAjKN3Tfw qeqWiY5kryThVqmCQHkHp8QdgNGdIqe7NgeZCTxrMq81SdUf+d0Q+PRSvKw850+vUa y8c2bjWdXenEQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Sasha Levin , Sashiko AI review , Lorenzo Stoakes , David Hildenbrand , Michal Hocko , Mike Rapoport , Peter Xu , Suren Baghdasaryan , Vlastimil Babka , Balbir Singh , Andrew Morton , Kiryl Shutsemau Subject: Re: [PATCH 7.1.y] userfaultfd: gate must_wait writability check on pte_present() Date: Fri, 3 Jul 2026 22:05:12 -0400 Message-ID: <2026070315-stable-reply-0018@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260702154908.975523-1-kas@kernel.org> References: <20260702154908.975523-1-kas@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, Jul 02, 2026 at 16:49:08 +0100, Kiryl Shutsemau wrote: > userfaultfd_must_wait() and userfaultfd_huge_must_wait() read the PTE > without taking the page table lock and then apply pte_write() / > huge_pte_write() to it. Those accessors decode bits from the present > encoding only; on a swap or migration entry they read the offset bits that > happen to share the same position and return an undefined result. Queued for 7.1.y, thanks! -- Thanks, Sasha