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 124FFC433F5 for ; Thu, 24 Mar 2022 21:33:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 47B076B0071; Thu, 24 Mar 2022 17:33:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 42AA96B0073; Thu, 24 Mar 2022 17:33:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F2276B0074; Thu, 24 Mar 2022 17:33:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 1ED0A6B0071 for ; Thu, 24 Mar 2022 17:33:05 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E1324206F4 for ; Thu, 24 Mar 2022 21:33:04 +0000 (UTC) X-FDA: 79280580288.11.4234F40 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf22.hostedemail.com (Postfix) with ESMTP id C35C2C0029 for ; Thu, 24 Mar 2022 21:33:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ZNh9mUSD119F1hcQ1c9te8DtDTYrhgO4FD2R2alLdsw=; b=cR6/luJzlOlQmjZ0FsCcz9k0Wo b62ukwJP90JJkQSM9G8IurwPFn8pc24yG3sZtdSzo08Eg8W713GSvolU4181PYKtopFDvIyoYBf09 sVTlKWo2SfNYh1V3n6XDC1ha1NouZGO2Fg3Hfu9Pzd+7Ycm/bMk7tX0ffpkptJNU4aDGmbVEWYvBs E0vdswIIND5t50Q5THqAYsLbEqwhnQUFVBvx4aGzlAl2wMiLRHyj6xa+DefOAV8b3HEsRV4mBcqhp KbU38u45kiCcJH5yoXtL3BPn4oB54svqYzJEHGKRqaTTn2lNEcpSayYt2W5WpwbaBIbaHxDENNwbH V2ngWzXg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nXV4i-00DlvS-Cw; Thu, 24 Mar 2022 21:32:56 +0000 Date: Thu, 24 Mar 2022 21:32:56 +0000 From: Matthew Wilcox To: Axel Rasmussen Cc: Andrew Morton , Mike Rapoport , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm/secretmem: fix panic when growing a memfd_secret Message-ID: References: <20220324210909.1843814-1-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220324210909.1843814-1-axelrasmussen@google.com> X-Stat-Signature: suouuacqbxf9d4ukzoti3aohsmrhfio8 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: C35C2C0029 Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="cR6/luJz"; dmarc=none; spf=none (imf22.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspam-User: X-HE-Tag: 1648157583-958981 X-Bogosity: Ham, tests=bogofilter, spamicity=0.330754, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Mar 24, 2022 at 02:09:09PM -0700, Axel Rasmussen wrote: > This patch avoids the panic by implementing a custom setattr for > memfd_secret, which detects resizes specifically (setting the size for > the first time works just fine, since there are no existing pages to try > to zero), and rejects them as not supported (ENOTSUP). Isn't ENOTTY the normal return value for this? Or even ENOSYS?