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,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 2B1DBC433DF for ; Mon, 17 Aug 2020 18:36:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EFE920578 for ; Mon, 17 Aug 2020 18:36:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597689373; bh=5oG2MmFI9L1HdIfGo8fU5jZd5SIfgs14NXF/ZzSQzKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Pi78JwEL2G9lyPi5gmTOmScX97I3XjsJWrijoWHhEiaZH8JMrR7qWPWTn8NZKdI8F J4cfnUh9xOrorR6TvaiMAJHqDHrSbVgCZbvuXZF8Lmng+dix/y5mADrwClWEI1iUJx tGc2uLSua54XqiY48uYct+K1D5hzvBGOP0i7A/xU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390778AbgHQSgJ (ORCPT ); Mon, 17 Aug 2020 14:36:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:46718 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730968AbgHQP71 (ORCPT ); Mon, 17 Aug 2020 11:59:27 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 AA347207FF; Mon, 17 Aug 2020 15:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597679967; bh=5oG2MmFI9L1HdIfGo8fU5jZd5SIfgs14NXF/ZzSQzKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=egshld41GUOvT/4TIKTdYJkCHrKO4hE6fpj84+rLYAi5K7rRrdfRfpbvbBMd9S5CA b2eDFTI/muCDws198ReKFqqPF6qKIq0wUzLFBpYiyr7JkkKXImbqMWIV8QzoWUaUm+ QVVpAkuZrScDI07Gf3XaBbRQSNIsn5oTa1Aj8pP4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+7f617d4a9369028b8a2c@syzkaller.appspotmail.com, Jens Axboe Subject: [PATCH 5.7 388/393] io_uring: sanitize double poll handling Date: Mon, 17 Aug 2020 17:17:18 +0200 Message-Id: <20200817143838.422623124@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143819.579311991@linuxfoundation.org> References: <20200817143819.579311991@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jens Axboe commit d4e7cd36a90e38e0276d6ce0c20f5ccef17ec38c upstream. There's a bit of confusion on the matching pairs of poll vs double poll, depending on if the request is a pure poll (IORING_OP_POLL_ADD) or poll driven retry. Add io_poll_get_double() that returns the double poll waitqueue, if any, and io_poll_get_single() that returns the original poll waitqueue. With that, remove the argument to io_poll_remove_double(). Finally ensure that wait->private is cleared once the double poll handler has run, so that remove knows it's already been seen. Cc: stable@vger.kernel.org # v5.8 Reported-by: syzbot+7f617d4a9369028b8a2c@syzkaller.appspotmail.com Fixes: 18bceab101ad ("io_uring: allow POLL_ADD with double poll_wait() users") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4233,9 +4233,24 @@ static bool io_poll_rewait(struct io_kio return false; } -static void io_poll_remove_double(struct io_kiocb *req, void *data) +static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req) { - struct io_poll_iocb *poll = data; + /* pure poll stashes this in ->io, poll driven retry elsewhere */ + if (req->opcode == IORING_OP_POLL_ADD) + return (struct io_poll_iocb *) req->io; + return req->apoll->double_poll; +} + +static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req) +{ + if (req->opcode == IORING_OP_POLL_ADD) + return &req->poll; + return &req->apoll->poll; +} + +static void io_poll_remove_double(struct io_kiocb *req) +{ + struct io_poll_iocb *poll = io_poll_get_double(req); lockdep_assert_held(&req->ctx->completion_lock); @@ -4255,7 +4270,7 @@ static void io_poll_complete(struct io_k { struct io_ring_ctx *ctx = req->ctx; - io_poll_remove_double(req, req->io); + io_poll_remove_double(req); req->poll.done = true; io_cqring_fill_event(req, error ? error : mangle_poll(mask)); io_commit_cqring(ctx); @@ -4297,7 +4312,7 @@ static int io_poll_double_wake(struct wa int sync, void *key) { struct io_kiocb *req = wait->private; - struct io_poll_iocb *poll = req->apoll->double_poll; + struct io_poll_iocb *poll = io_poll_get_single(req); __poll_t mask = key_to_poll(key); /* for instances that support it check for an event match first: */ @@ -4311,6 +4326,8 @@ static int io_poll_double_wake(struct wa done = list_empty(&poll->wait.entry); if (!done) list_del_init(&poll->wait.entry); + /* make sure double remove sees this as being gone */ + wait->private = NULL; spin_unlock(&poll->head->lock); if (!done) __io_async_wake(req, poll, mask, io_poll_task_func); @@ -4545,7 +4562,7 @@ static bool io_arm_poll_handler(struct i ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, io_async_wake); if (ret || ipt.error) { - io_poll_remove_double(req, apoll->double_poll); + io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); memcpy(&req->work, &apoll->work, sizeof(req->work)); kfree(apoll->double_poll); @@ -4578,14 +4595,13 @@ static bool io_poll_remove_one(struct io { bool do_complete; + io_poll_remove_double(req); + if (req->opcode == IORING_OP_POLL_ADD) { - io_poll_remove_double(req, req->io); do_complete = __io_poll_remove_one(req, &req->poll); } else { struct async_poll *apoll = req->apoll; - io_poll_remove_double(req, apoll->double_poll); - /* non-poll requests have submit ref still */ do_complete = __io_poll_remove_one(req, &apoll->poll); if (do_complete) {