Return-Path: 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 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-Type: text/plain; charset=us-ascii From: bfields@fieldses.org (J. Bruce Fields) Sender: linux-nfs-owner@vger.kernel.org List-ID: 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; -- 2.5.0