From patchwork Thu Mar 17 18:35:55 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 8613861 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EF431C0553 for ; Thu, 17 Mar 2016 18:36:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 352512022A for ; Thu, 17 Mar 2016 18:36:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C0822020F for ; Thu, 17 Mar 2016 18:36:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935663AbcCQSgB (ORCPT ); Thu, 17 Mar 2016 14:36:01 -0400 Received: from fieldses.org ([173.255.197.46]:35046 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935629AbcCQSf6 (ORCPT ); Thu, 17 Mar 2016 14:35:58 -0400 Received: by fieldses.org (Postfix, from userid 2815) id 11FEE1CC9; Thu, 17 Mar 2016 14:35:55 -0400 (EDT) Date: Thu, 17 Mar 2016 14:35:55 -0400 To: linux-nfs@vger.kernel.org Subject: [PATCH] nfsd: fix deadlock secinfo+readdir compound Message-ID: <20160317183555.GA25906@fieldses.org> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "J. Bruce Fields" nfsd_lookup_dentry exits with the parent filehandle locked. fh_put also unlocks if necessary (nfsd filehandle locking is probably too lenient), so it gets unlocked eventually, but if the following op in the compound needs to lock it again, we can deadlock. A fuzzer ran into this; normal clients don't send a secinfo followed by a readdir in the same compound. Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4proc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 410516e9867f..40b912407d51 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -876,6 +876,7 @@ nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, &exp, &dentry); if (err) return err; + fh_unlock(&cstate->current_fh); if (d_really_is_negative(dentry)) { exp_put(exp); err = nfserr_noent;