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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4BED1C433E7 for ; Mon, 12 Oct 2020 14:05:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1580F208FE for ; Mon, 12 Oct 2020 14:05:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602511541; bh=nwsihx0hEKKxGCYZPIMOabEyuW0LWmS5jhpfaKWmdDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=17OPG/6RXl1Q5MqNisZ8CQM7jJnUHsmJ03jT0VlaOTcIWG3I+oDhG89cnvddGZEob sVcySv2z36xw/d9rJ/v7pAP5ropgeDU2tLECuFctAx3WDF5ImI+156q2UvpksUKhW/ 49yEgdonbo4JR1z2J6dzC6Pn7GQdvvovTnbArado= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391003AbgJLOFk (ORCPT ); Mon, 12 Oct 2020 10:05:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:37490 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726963AbgJLNe4 (ORCPT ); Mon, 12 Oct 2020 09:34:56 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AB17D20678; Mon, 12 Oct 2020 13:34:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602509696; bh=nwsihx0hEKKxGCYZPIMOabEyuW0LWmS5jhpfaKWmdDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NAZZc2NEgdNX36YFovuC76tsM0WjLZ7JbphTcWer0SQFTn682aUMFvAu1Nl6BQwao jBR2aLbde6tRwN/S53cBOYIZz4PFWXZ1m6bRwDGW4/uPPrsNmiaKUU0iAqEZc3yAxU 4eCXkTcRSVlNApPhGx6L/arc1vZ+Z7gw/VxC4+jk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 4.9 18/54] epoll: do not insert into poll queues until all sanity checks are done Date: Mon, 12 Oct 2020 15:26:40 +0200 Message-Id: <20201012132630.437902095@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012132629.585664421@linuxfoundation.org> References: <20201012132629.585664421@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: stable@vger.kernel.org From: Al Viro commit f8d4f44df056c5b504b0d49683fb7279218fd207 upstream. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/eventpoll.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1332,6 +1332,22 @@ static int ep_insert(struct eventpoll *e RCU_INIT_POINTER(epi->ws, NULL); } + /* Add the current item to the list of active epoll hook for this file */ + spin_lock(&tfile->f_lock); + list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); + spin_unlock(&tfile->f_lock); + + /* + * Add the current item to the RB tree. All RB tree operations are + * protected by "mtx", and ep_insert() is called with "mtx" held. + */ + ep_rbtree_insert(ep, epi); + + /* now check if we've created too many backpaths */ + error = -EINVAL; + if (full_check && reverse_path_check()) + goto error_remove_epi; + /* Initialize the poll table using the queue callback */ epq.epi = epi; init_poll_funcptr(&epq.pt, ep_ptable_queue_proc); @@ -1354,22 +1370,6 @@ static int ep_insert(struct eventpoll *e if (epi->nwait < 0) goto error_unregister; - /* Add the current item to the list of active epoll hook for this file */ - spin_lock(&tfile->f_lock); - list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links); - spin_unlock(&tfile->f_lock); - - /* - * Add the current item to the RB tree. All RB tree operations are - * protected by "mtx", and ep_insert() is called with "mtx" held. - */ - ep_rbtree_insert(ep, epi); - - /* now check if we've created too many backpaths */ - error = -EINVAL; - if (full_check && reverse_path_check()) - goto error_remove_epi; - /* We have to drop the new item inside our item list to keep track of it */ spin_lock_irqsave(&ep->lock, flags); @@ -1395,6 +1395,8 @@ static int ep_insert(struct eventpoll *e return 0; +error_unregister: + ep_unregister_pollwait(ep, epi); error_remove_epi: spin_lock(&tfile->f_lock); list_del_rcu(&epi->fllink); @@ -1402,9 +1404,6 @@ error_remove_epi: rb_erase(&epi->rbn, &ep->rbr); -error_unregister: - ep_unregister_pollwait(ep, epi); - /* * We need to do this because an event could have been arrived on some * allocated wait queue. Note that we don't care about the ep->ovflist