From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41840C5B543 for ; Sat, 7 Jun 2025 14:40:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA4136B0092; Sat, 7 Jun 2025 10:40:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B54ED6B0093; Sat, 7 Jun 2025 10:40:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6AF36B0095; Sat, 7 Jun 2025 10:40:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 882E76B0092 for ; Sat, 7 Jun 2025 10:40:28 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 2D316A05D4 for ; Sat, 7 Jun 2025 14:40:28 +0000 (UTC) X-FDA: 83528865336.03.8FD0B24 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf17.hostedemail.com (Postfix) with ESMTP id 687014000C for ; Sat, 7 Jun 2025 14:40:26 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=zx2c4.com header.s=20210105 header.b=OWwSzy+G; spf=pass (imf17.hostedemail.com: domain of "SRS0=cnMf=YW=zx2c4.com=Jason@kernel.org" designates 172.234.252.31 as permitted sender) smtp.mailfrom="SRS0=cnMf=YW=zx2c4.com=Jason@kernel.org"; dmarc=pass (policy=quarantine) header.from=zx2c4.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749307226; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Kq41Ond10mXUHWVV/vnahXJAC8HnwJxzy4Wdqc+zAVc=; b=rbYJnOYqvu5yjAUf/nl8ZPNuKzoYWnLyW78UBDKZ6RBwUVxxcn3ERCHIGgrkeLlLcUR+o0 hPpdQfNiJduNVEVA64rXoghxIyia1PATlzyR96Pv6Si2MrFVq1FDSxHlKunrCU8ub5T850 Iu69srO5c3NxBHosDdrHz0GrUOf8ufQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1749307226; a=rsa-sha256; cv=none; b=Xj7+CpAR2K8wYt3i+87EYjr0TlKvnaCqECPB54uMpmtLBEZqH7hDElqknJSnJJBjV8pVm4 jeC5sT/cpv2B6SZeEO49ptBiaKzCd3P4k5Mbrw5Yc8h7S7AcmgzJ7whZGMy6PxjxPg3ccu XckOezFXDjcIEntA34EcVztXIAKvngI= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=zx2c4.com header.s=20210105 header.b=OWwSzy+G; spf=pass (imf17.hostedemail.com: domain of "SRS0=cnMf=YW=zx2c4.com=Jason@kernel.org" designates 172.234.252.31 as permitted sender) smtp.mailfrom="SRS0=cnMf=YW=zx2c4.com=Jason@kernel.org"; dmarc=pass (policy=quarantine) header.from=zx2c4.com Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id EAFA0439CF; Sat, 7 Jun 2025 14:40:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABF05C4CEE4; Sat, 7 Jun 2025 14:40:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1749307220; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Kq41Ond10mXUHWVV/vnahXJAC8HnwJxzy4Wdqc+zAVc=; b=OWwSzy+G/TwmeEFLU5ro4fU/JkjaYJImSIS6NF39LxjoYpH8t/GbwTaTCh0m7Dwu6qXHL4 ETAF0onYqtUwYWf3Jxo/egSURAGAmAeFj37SDswL3aH1vyZyffarqRmHOoVREP0Ea5o7il 3SPTTyr0oqkqBKvcMrcuyakjOCMdmOU= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id eef4a3a4 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sat, 7 Jun 2025 14:40:20 +0000 (UTC) Date: Sat, 7 Jun 2025 08:40:14 -0600 From: "Jason A. Donenfeld" To: Tal Zussman Cc: Andrew Morton , Peter Xu , David Hildenbrand , Alexander Viro , Christian Brauner , Jan Kara , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 1/4] userfaultfd: correctly prevent registering VM_DROPPABLE regions Message-ID: References: <20250607-uffd-fixes-v2-0-339dafe9a2fe@columbia.edu> <20250607-uffd-fixes-v2-1-339dafe9a2fe@columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250607-uffd-fixes-v2-1-339dafe9a2fe@columbia.edu> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 687014000C X-Stat-Signature: axk5jjximdqfeq6kk1ewgza6dsbmkchk X-Rspam-User: X-HE-Tag: 1749307226-522857 X-HE-Meta: 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 5/grkUKN dvg9g433Q/HLLFF0uNEsNOopZHVydbI8fCqLR8+eWlna5PvA6W6nox986YmUr9OEli8sKck2iJ73igO7w7PeyYN/4liU/4SC7A5ObkAP2A321kuYxQHldFhpKzvTdzYWN+Qi8osezZtX7U1pX28AYhJ75QJn6V7vC2nkqEcsHJBsZYBd9MxYdIBRMYQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Jun 07, 2025 at 02:40:00AM -0400, Tal Zussman wrote: > vma_can_userfault() masks off non-userfaultfd VM flags from vm_flags. > The vm_flags & VM_DROPPABLE test will then always be false, incorrectly > allowing VM_DROPPABLE regions to be registered with userfaultfd. > > Additionally, vm_flags is not guaranteed to correspond to the actual > VMA's flags. Fix this test by checking the VMA's flags directly. > > Link: https://lore.kernel.org/linux-mm/5a875a3a-2243-4eab-856f-bc53ccfec3ea@redhat.com/ > Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings") > Acked-by: David Hildenbrand > Acked-by: Peter Xu > Signed-off-by: Tal Zussman Nice catch and thanks for fixing this. Acked-by: Jason A. Donenfeld