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 367673431EF for ; Sat, 4 Jul 2026 02:05:51 +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=1783130753; cv=none; b=uxPYCWwCr4lwkws4+EHVSwhvyoo+mdt6cuRlX7qmkY/HwZsgN+lmYEquxSUnXz8ODLqLTTvuTbfoVXwKTFhF0vTj/e3jPNm5wuh9NrgOYW1Q/9XR4xOX5AoY8eT9dsqZ9E5E4MRWLgx+BTsTeV9ps1lhikLv7stnZz4L4clPHXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783130753; c=relaxed/simple; bh=Q3ox1ykldMB+RPfbyJfbbmtpYBFHtLCejRo0F7ZvOLA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o1m23GONfmSFs4a5sxjVZ+KknqHTBWs7/bLtHOAdFjmeLVIKdQBjNarPnLKtyYlIwUXGjGENjdMEX2RM8k+G+saCMiBfiL/PjOQjdzR20n3rYeG+cdJ9HuyqLcdFxeaB6FvAsx7dgSw9i6BEjBW/dPBeUmi8CdEJ9O4LvhtX+yk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fMGXJ6m6; 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="fMGXJ6m6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72D431F000E9; Sat, 4 Jul 2026 02:05:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783130751; bh=dbG8pPJZPyZe1HUmxzeVIu/5PHJoTNcjJhS47UFBiIM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fMGXJ6m6Xdbrs3kCMegcRvn6ajfD5xGM3UaqHjr94aLpqZjDAsZdBv+PW4vWtD/l1 tIPh3LWppoS+VjcTy/T2tV7YOQFDvVieERqt8SegbHCnAr+QM00j0x41BnxeShv4DZ 9mK9YYjW3Q1EdyupAQkC1FtjM6cyfpvvyYjSNIoIKSLPUivf1IEcHQwRuyFfxF5PqA kIE4S+vdxkq8XakHquIEuQFPFWGedOHLJ2RpcxfNZJEmvstQOFb7R7TPzuWDQlzPGG rGSLI/rVLw2ABfmO/ZX0+SPEdVMZWA/jXWLhQ/eJSy+8NMxirbcmuz6n3684YDyqel 9P5DnCnAvzAaQ== 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 6.12.y] userfaultfd: gate must_wait writability check on pte_present() Date: Fri, 3 Jul 2026 22:05:14 -0400 Message-ID: <2026070315-stable-reply-0020@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260702154905.975477-1-kas@kernel.org> References: <20260702154905.975477-1-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 16:49:05 +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 6.12.y, thanks! -- Thanks, Sasha