Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759342AbcDBBSt (ORCPT ); Fri, 1 Apr 2016 21:18:49 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54303 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932576AbcDBA4T (ORCPT ); Fri, 1 Apr 2016 20:56:19 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "J . Bruce Fields" , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 097/170] nfsd: fix deadlock secinfo+readdir compound Date: Fri, 1 Apr 2016 17:53:03 -0700 Message-Id: <1459558456-24452-98-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1459558456-24452-1-git-send-email-kamal@canonical.com> References: <1459558456-24452-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1185 Lines: 36 3.19.8-ckt18 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: "J. Bruce Fields" commit 2f6fc056e899bd0144a08da5cacaecbe8997cd74 upstream. 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. Signed-off-by: J. Bruce Fields Signed-off-by: Kamal Mostafa --- fs/nfsd/nfs4proc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 2cd2d64..7ef7c18 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -879,6 +879,7 @@ nfsd4_secinfo(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, &exp, &dentry); if (err) return err; + fh_unlock(&cstate->current_fh); if (dentry->d_inode == NULL) { exp_put(exp); err = nfserr_noent; -- 2.7.4