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=-10.5 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 950E9C4363A for ; Mon, 5 Oct 2020 15:30:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 585F820B80 for ; Mon, 5 Oct 2020 15:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601911840; bh=pVLhw7rbKHNqkrFfSEGlR055tsd2zEIAiNY+yfzBifw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZYiXX638lDX0yx7Xz0Z0VTV7vWlSFQZ4DY1A2vS8JF2jy1mpHyEf/aLG0Y8h4UkcD 1xFSiPJBawtqrulRRQg2ec22pZ3bc+xhPCmFvLF6HcIebUwCqULTben451ejGk42YY ipWjli2wUGYnVWs0A9b+Jk056drWjoFnO0nJ5LYg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727296AbgJEPah (ORCPT ); Mon, 5 Oct 2020 11:30:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:56912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727764AbgJEPa1 (ORCPT ); Mon, 5 Oct 2020 11:30:27 -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 DE9E220637; Mon, 5 Oct 2020 15:30:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601911826; bh=pVLhw7rbKHNqkrFfSEGlR055tsd2zEIAiNY+yfzBifw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QHafvJ5zkah82LfzyhVUWSFIxsalB4vnsEnR5QBFej53TsLEyI8mnlgBQW/W/JwWI mUJyBKUP47v4rOxdwnnCMlu1ZI840hvgrBKDrVJmODiTrfF2VxbOaxTaeUakMQMaRW Et3FZdi3DywxFTgY/BEDf8Hq+KaTQXChv94y1XFg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 5.4 53/57] epoll: do not insert into poll queues until all sanity checks are done Date: Mon, 5 Oct 2020 17:27:05 +0200 Message-Id: <20201005142112.350059875@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201005142109.796046410@linuxfoundation.org> References: <20201005142109.796046410@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: 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 @@ -1527,6 +1527,22 @@ 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); @@ -1549,22 +1565,6 @@ 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 */ write_lock_irq(&ep->lock); @@ -1593,6 +1593,8 @@ 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); @@ -1600,9 +1602,6 @@ error_remove_epi: rb_erase_cached(&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