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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 EF3EDC2BBE2 for ; Sun, 8 Dec 2019 13:58:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFCFD20726 for ; Sun, 8 Dec 2019 13:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727349AbfLHN6W (ORCPT ); Sun, 8 Dec 2019 08:58:22 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60094 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbfLHNyl (ORCPT ); Sun, 8 Dec 2019 08:54:41 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1idx1C-0007dp-4a; Sun, 08 Dec 2019 13:54:38 +0000 Received: from ben by deadeye with local (Exim 4.93-RC1) (envelope-from ) id 1idx1B-0002MP-7u; Sun, 08 Dec 2019 13:54:37 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Eric Biggers" , syzbot+0eefc1e06a77d327a056@syzkaller.appspotmail.com, "Casey Schaufler" Date: Sun, 08 Dec 2019 13:53:09 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 25/72] smack: use GFP_NOFS while holding inode_smack::smk_lock In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.79-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit e5bfad3d7acc5702f32aafeb388362994f4d7bd0 upstream. inode_smack::smk_lock is taken during smack_d_instantiate(), which is called during a filesystem transaction when creating a file on ext4. Therefore to avoid a deadlock, all code that takes this lock must use GFP_NOFS, to prevent memory reclaim from waiting for the filesystem transaction to complete. Reported-by: syzbot+0eefc1e06a77d327a056@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Signed-off-by: Casey Schaufler [bwh: Backported to 3.16: - Drop change to smk_netlbl_mls(), where GFP_ATOMIC is used - Adjust context] Signed-off-by: Ben Hutchings --- --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -430,7 +430,7 @@ char *smk_parse_smack(const char *string if (i == 0 || i >= SMK_LONGLABEL) return NULL; - smack = kzalloc(i + 1, GFP_KERNEL); + smack = kzalloc(i + 1, GFP_NOFS); if (smack != NULL) { strncpy(smack, string, i + 1); smack[i] = '\0'; @@ -502,7 +502,7 @@ struct smack_known *smk_import_entry(con if (skp != NULL) goto freeout; - skp = kzalloc(sizeof(*skp), GFP_KERNEL); + skp = kzalloc(sizeof(*skp), GFP_NOFS); if (skp == NULL) goto freeout; --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -70,7 +70,7 @@ static struct smack_known *smk_fetch(con if (ip->i_op->getxattr == NULL) return NULL; - buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL); + buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS); if (buffer == NULL) return NULL;