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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D12DC43334 for ; Fri, 3 Jun 2022 17:43:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344669AbiFCRnE (ORCPT ); Fri, 3 Jun 2022 13:43:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344852AbiFCRmU (ORCPT ); Fri, 3 Jun 2022 13:42:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B367E54193; Fri, 3 Jun 2022 10:41:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A6A9861AFB; Fri, 3 Jun 2022 17:41:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0231C385A9; Fri, 3 Jun 2022 17:41:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654278092; bh=47+WW93izh9zYfS6/3qjMleBfy11harY9ZN6Ja4SPOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SkNMdNw55N4RaBc2BY4pb2Mdqc9zPmlnm96a9xBytDHCTos8756TCpn6/zAODtR+T C+9QXpdAiZbFz9/rfn+LmgXuJvdNwPX88QyRMcWrI5oPyXsjUqdv9KDf+yZvqtyu3+ WR05zqzzhJrpk0D/1PmMuiY8UNmDdhdttj8CCxrw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dai Ngo , Chuck Lever Subject: [PATCH 4.14 22/23] NFSD: Fix possible sleep during nfsd4_release_lockowner() Date: Fri, 3 Jun 2022 19:39:49 +0200 Message-Id: <20220603173815.032974590@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220603173814.362515009@linuxfoundation.org> References: <20220603173814.362515009@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chuck Lever commit ce3c4ad7f4ce5db7b4f08a1e237d8dd94b39180b upstream. nfsd4_release_lockowner() holds clp->cl_lock when it calls check_for_locks(). However, check_for_locks() calls nfsd_file_get() / nfsd_file_put() to access the backing inode's flc_posix list, and nfsd_file_put() can sleep if the inode was recently removed. Let's instead rely on the stateowner's reference count to gate whether the release is permitted. This should be a reliable indication of locks-in-use since file lock operations and ->lm_get_owner take appropriate references, which are released appropriately when file locks are removed. Reported-by: Dai Ngo Signed-off-by: Chuck Lever Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4state.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6351,16 +6351,12 @@ nfsd4_release_lockowner(struct svc_rqst if (sop->so_is_open_owner || !same_owner_str(sop, owner)) continue; - /* see if there are still any locks associated with it */ - lo = lockowner(sop); - list_for_each_entry(stp, &sop->so_stateids, st_perstateowner) { - if (check_for_locks(stp->st_stid.sc_file, lo)) { - status = nfserr_locks_held; - spin_unlock(&clp->cl_lock); - return status; - } + if (atomic_read(&sop->so_count) != 1) { + spin_unlock(&clp->cl_lock); + return nfserr_locks_held; } + lo = lockowner(sop); nfs4_get_stateowner(sop); break; }