From owner-svn-src-stable@freebsd.org Sat May 7 20:09:16 2016 Return-Path: Delivered-To: svn-src-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DD45AB32910; Sat, 7 May 2016 20:09:16 +0000 (UTC) (envelope-from rmacklem@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 8CE051D03; Sat, 7 May 2016 20:09:16 +0000 (UTC) (envelope-from rmacklem@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u47K9FZS032275; Sat, 7 May 2016 20:09:15 GMT (envelope-from rmacklem@FreeBSD.org) Received: (from rmacklem@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u47K9FJv032273; Sat, 7 May 2016 20:09:15 GMT (envelope-from rmacklem@FreeBSD.org) Message-Id: <201605072009.u47K9FJv032273@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: rmacklem set sender to rmacklem@FreeBSD.org using -f From: Rick Macklem Date: Sat, 7 May 2016 20:09:15 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r299222 - in stable/10/sys/fs: nfs nfsserver X-SVN-Group: stable-10 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 07 May 2016 20:09:17 -0000 Author: rmacklem Date: Sat May 7 20:09:15 2016 New Revision: 299222 URL: https://svnweb.freebsd.org/changeset/base/299222 Log: MFC: r298495 Fix a LOR in the NFSv4.1 server. The ordering of acquisition of the state and session mutexes was reversed in two cases executed when an NFSv4.1 client created/freed a session. Since clients will typically do this only when mounting and dismounting, the likelyhood of causing a deadlock was low but possible. This can only occur for NFSv4.1 mounts, since the others do not use sessions. This was detected while testing the pNFS server/client where the client crashed during dismounting. The patch also reorders the unlocks, although that isn't necessary for correct operation. Modified: stable/10/sys/fs/nfs/nfsrvstate.h stable/10/sys/fs/nfsserver/nfs_nfsdstate.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/fs/nfs/nfsrvstate.h ============================================================================== --- stable/10/sys/fs/nfs/nfsrvstate.h Sat May 7 19:05:39 2016 (r299221) +++ stable/10/sys/fs/nfs/nfsrvstate.h Sat May 7 20:09:15 2016 (r299222) @@ -113,7 +113,7 @@ struct nfsclient { * Structure for an NFSv4.1 session. * Locking rules for this structure. * To add/delete one of these structures from the lists, you must lock - * both: NFSLOCKSESSION(session hashhead) and NFSLOCKSTATE() in that order. + * both: NFSLOCKSTATE() and NFSLOCKSESSION(session hashhead) in that order. * To traverse the lists looking for one of these, you must hold one * of these two locks. * The exception is if the thread holds the exclusive root sleep lock. Modified: stable/10/sys/fs/nfsserver/nfs_nfsdstate.c ============================================================================== --- stable/10/sys/fs/nfsserver/nfs_nfsdstate.c Sat May 7 19:05:39 2016 (r299221) +++ stable/10/sys/fs/nfsserver/nfs_nfsdstate.c Sat May 7 20:09:15 2016 (r299222) @@ -629,13 +629,13 @@ nfsrv_getclient(nfsquad_t clientid, int NFSBCOPY(sessid, nsep->sess_cbsess.nfsess_sessionid, NFSX_V4SESSIONID); shp = NFSSESSIONHASH(nsep->sess_sessionid); + NFSLOCKSTATE(); NFSLOCKSESSION(shp); LIST_INSERT_HEAD(&shp->list, nsep, sess_hash); - NFSLOCKSTATE(); LIST_INSERT_HEAD(&clp->lc_session, nsep, sess_list); nsep->sess_clp = clp; - NFSUNLOCKSTATE(); NFSUNLOCKSESSION(shp); + NFSUNLOCKSTATE(); } } } else if (clp->lc_flags & LCL_NEEDSCONFIRM) { @@ -5915,6 +5915,7 @@ nfsrv_freesession(struct nfsdsession *se struct nfssessionhash *shp; int i; + NFSLOCKSTATE(); if (sep == NULL) { shp = NFSSESSIONHASH(sessionid); NFSLOCKSESSION(shp); @@ -5924,18 +5925,17 @@ nfsrv_freesession(struct nfsdsession *se NFSLOCKSESSION(shp); } if (sep != NULL) { - NFSLOCKSTATE(); sep->sess_refcnt--; if (sep->sess_refcnt > 0) { - NFSUNLOCKSTATE(); NFSUNLOCKSESSION(shp); + NFSUNLOCKSTATE(); return (0); } LIST_REMOVE(sep, sess_hash); LIST_REMOVE(sep, sess_list); - NFSUNLOCKSTATE(); } NFSUNLOCKSESSION(shp); + NFSUNLOCKSTATE(); if (sep == NULL) return (NFSERR_BADSESSION); for (i = 0; i < NFSV4_SLOTS; i++)