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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3F51C43331 for ; Thu, 5 Sep 2019 18:36:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AB0FE20825 for ; Thu, 5 Sep 2019 18:36:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="sv6J0GiU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB0FE20825 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZuGyhfYrvahbGgB9Dy7/AfkehQ0m4JC3D9kCyEiQaEk=; b=sv6J0GiULCWwmx 5TLNRbznChKBA1XRVq66q9btlLWt3cdajOZ+PS+h/Aywgfl2GQ/pc5psAPXbY4zvXdSvDtklLbYgZ tJ/B2Fb9rIUQcvp+MHydLMe2EEY1b0kYBfOYXv6BmUjIWQXWxkk62oHWz/glbl9YKb0JgcOerCN0v THA8CDpJqDktW0OsSMbUz10qESg7nUIjig09pe+1UuICI8TnHSyyLm5t1oCS5qIkKeGRUVE9VxFrK /2GGRqyr1QN0dLZNuDytD4LjCiGr1Yti08SBqiqD0f124/J9i5mjTzpl32jtA9TSUinRckHWTQURZ hCU8zdQnbgRdh2xav99g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i5wc3-0006lA-PM; Thu, 05 Sep 2019 18:36:07 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i5wc1-0006kF-5b for linux-arm-kernel@lists.infradead.org; Thu, 05 Sep 2019 18:36:06 +0000 Received: from [46.114.37.115] (helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1i5wbZ-0006Ee-52; Thu, 05 Sep 2019 18:35:37 +0000 Date: Thu, 5 Sep 2019 20:35:32 +0200 From: Christian Brauner To: Al Viro Subject: Re: [PATCH v12 01/12] lib: introduce copy_struct_{to,from}_user helpers Message-ID: <20190905183532.GA25049@localhost> References: <20190904201933.10736-1-cyphar@cyphar.com> <20190904201933.10736-2-cyphar@cyphar.com> <20190905180750.GQ1131@ZenIV.linux.org.uk> <20190905182303.7f6bxpa2enbgcegv@wittgenstein> <20190905182801.GR1131@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190905182801.GR1131@ZenIV.linux.org.uk> User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190905_113605_349589_81C64CE0 X-CRM114-Status: GOOD ( 14.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Rasmus Villemoes , Alexei Starovoitov , linux-kernel@vger.kernel.org, David Howells , linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Shuah Khan , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Tycho Andersen , Aleksa Sarai , Jiri Olsa , Alexander Shishkin , Ingo Molnar , linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-xtensa@linux-xtensa.org, Kees Cook , Arnd Bergmann , Jann Horn , linuxppc-dev@lists.ozlabs.org, Aleksa Sarai , Andy Lutomirski , Shuah Khan , Namhyung Kim , David Drysdale , Christian Brauner , "J. Bruce Fields" , linux-parisc@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-api@vger.kernel.org, Chanho Min , Jeff Layton , Oleg Nesterov , Eric Biederman , linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Linus Torvalds , containers@lists.linux-foundation.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Sep 05, 2019 at 07:28:01PM +0100, Al Viro wrote: > On Thu, Sep 05, 2019 at 08:23:03PM +0200, Christian Brauner wrote: > > > Because every caller of that function right now has that limit set > > anyway iirc. So we can either remove it from here and place it back for > > the individual callers or leave it in the helper. > > Also, I'm really asking, why not? Is it unreasonable to have an upper > > bound on the size (for a long time probably) or are you disagreeing with > > PAGE_SIZE being used? PAGE_SIZE limit is currently used by sched, perf, > > bpf, and clone3 and in a few other places. > > For a primitive that can be safely used with any size (OK, any within > the usual 2Gb limit)? Why push the random policy into the place where > it doesn't belong? Ah, the "not in the helper part" makes sense. As long as leave the check for the callers themselves. > > Seriously, what's the point? If they want to have a large chunk of > userland memory zeroed or checked for non-zeroes - why would that > be a problem? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel