From patchwork Mon Dec 28 12:48:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 354795 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, 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 3453EC4332D for ; Mon, 28 Dec 2020 14:44:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDCB6221F0 for ; Mon, 28 Dec 2020 14:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392069AbgL1Ool (ORCPT ); Mon, 28 Dec 2020 09:44:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:32850 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503162AbgL1OY5 (ORCPT ); Mon, 28 Dec 2020 09:24:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A387422AEC; Mon, 28 Dec 2020 14:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165457; bh=pMvmUkbPIgx+8nGnsq2F0E4jxQfgWmKkiJllS1egw94=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lriEL4bP3RTKKZfCh4aRBHoZRECLZ3g+La2y2Mde9h/gyW2tnxo5In37wnjPjAJlz q4qgVzXF7CLdfuieew36MvkMWGVIY2H8oRN9XsOJGhs12PztJsgkpIvAMIW3EBaLzA YhP2/mdPiw7qdWuIZ5Tj7CJpYgVxMDBWs8QjRJa4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Begunkov , Jens Axboe Subject: [PATCH 5.10 511/717] io_uring: fix racy IOPOLL completions Date: Mon, 28 Dec 2020 13:48:29 +0100 Message-Id: <20201228125045.447543868@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Begunkov commit 31bff9a51b264df6d144931a6a5f1d6cc815ed4b upstream. IOPOLL allows buffer remove/provide requests, but they doesn't synchronise by rules of IOPOLL, namely it have to hold uring_lock. Cc: # 5.7+ Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3944,11 +3944,17 @@ static int io_remove_buffers(struct io_k head = idr_find(&ctx->io_buffer_idr, p->bgid); if (head) ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs); - - io_ring_submit_lock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); - __io_req_complete(req, ret, 0, cs); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + __io_req_complete(req, ret, 0, cs); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + __io_req_complete(req, ret, 0, cs); + } return 0; } @@ -4033,10 +4039,17 @@ static int io_provide_buffers(struct io_ } } out: - io_ring_submit_unlock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); - __io_req_complete(req, ret, 0, cs); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + __io_req_complete(req, ret, 0, cs); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + __io_req_complete(req, ret, 0, cs); + } return 0; }