From patchwork Tue Oct 13 23:52:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11836343 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E1FB5921 for ; Tue, 13 Oct 2020 23:52:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A0155221FF for ; Tue, 13 Oct 2020 23:52:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="xqcGkgKJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A0155221FF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 609B56B00B6; Tue, 13 Oct 2020 19:52:04 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 5B9476B00B7; Tue, 13 Oct 2020 19:52:04 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 48060900002; Tue, 13 Oct 2020 19:52:04 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0083.hostedemail.com [216.40.44.83]) by kanga.kvack.org (Postfix) with ESMTP id 11BDD6B00B6 for ; Tue, 13 Oct 2020 19:52:04 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AE3831EE6 for ; Tue, 13 Oct 2020 23:52:03 +0000 (UTC) X-FDA: 77368552926.05.day40_121253b27207 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 8B71818016695 for ; Tue, 13 Oct 2020 23:52:03 +0000 (UTC) X-Spam-Summary: 1,0,0,2af132fccec75a78,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1345:1359:1381:1431:1437:1534:1541:1711:1730:1747:1777:1792:2393:2525:2559:2563:2682:2685:2859:2897:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3353:3865:3866:3867:3868:3871:3872:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:5007:6261:6653:7514:7576:7903:7974:8784:9025:9545:10004:11026:11473:11658:11914:12043:12048:12297:12517:12519:12555:12679:12986:13069:13311:13357:13846:14181:14384:14721:21080:21451:21627:21939:21990:30054:30064:30070,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-64.100.201.201 62.2.0.100;04yrmx6mhgrdbragtjgrh4mr4xfehoc1z8mjw7smmdkin153qor4zzke45tqn1f.1o54a6ybkdjo499w75rk8jeoske3kzjbcac4hcpr74tfk7g9etd786s7g6fog83.y-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0 ,LFtime: X-HE-Tag: day40_121253b27207 X-Filterd-Recvd-Size: 3023 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 23:52:03 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 362C422200; Tue, 13 Oct 2020 23:52:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633122; bh=5q4yq1WqrA1fxYozEfb1M0AZwwgjjeqV0S0X3cFTOAs=; h=Date:From:To:Subject:In-Reply-To:From; b=xqcGkgKJbGa1y4iIfQlVMfEI1rqpprAVTRPec32R/Fq1a1HA8EP8tKZ3xD5dGntZs 9xIqIb2IAMaX3usC3wTuxlRXW7AQIARol41CErmAlB13bW8NtlHcWTxp2s+v8HQDrC 8s7Ubzb0HsBJfbuqz8SmPaGyzHaYBDvIBJf/0pa0= Date: Tue, 13 Oct 2020 16:52:01 -0700 From: Andrew Morton To: akpm@linux-foundation.org, dan.carpenter@oracle.com, ira.weiny@intel.com, jhubbard@nvidia.com, jrdr.linux@gmail.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 067/181] mm/gup: protect unpin_user_pages() against npages==-ERRNO Message-ID: <20201013235201.FZrZ9P783%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: John Hubbard Subject: mm/gup: protect unpin_user_pages() against npages==-ERRNO As suggested by Dan Carpenter, fortify unpin_user_pages() just a bit, against a typical caller mistake: check if the npages arg is really a -ERRNO value, which would blow up the unpinning loop: WARN and return. If this new WARN_ON() fires, then the system *might* be leaking pages (by leaving them pinned), but probably not. More likely, gup/pup returned a hard -ERRNO error to the caller, who erroneously passed it here. Link: https://lkml.kernel.org/r/20200917065706.409079-1-jhubbard@nvidia.com Signed-off-by: John Hubbard Signed-off-by: Dan Carpenter Cc: Ira Weiny Cc: Souptick Joarder Signed-off-by: Andrew Morton --- mm/gup.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/mm/gup.c~mm-gup-protect-unpin_user_pages-against-npages==-errno +++ a/mm/gup.c @@ -329,6 +329,13 @@ void unpin_user_pages(struct page **page unsigned long index; /* + * If this WARN_ON() fires, then the system *might* be leaking pages (by + * leaving them pinned), but probably not. More likely, gup/pup returned + * a hard -ERRNO error to the caller, who erroneously passed it here. + */ + if (WARN_ON(IS_ERR_VALUE(npages))) + return; + /* * TODO: this can be optimized for huge pages: if a series of pages is * physically contiguous and part of the same compound page, then a * single operation to the head page should suffice.