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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 17F0FC43387 for ; Thu, 20 Dec 2018 09:24:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFBA1217D7 for ; Thu, 20 Dec 2018 09:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545297897; bh=G5b1ayP4DqY4gNdUN0MrK1ob1Adeyj75jVxspDedqZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UbKQeM5U1mRrV9kuyIK2+1Q0GqEk3tvB4pAQNlUPfMljlbpStyCKJNYcb1NT8hpQo kwGvZxKJ/IDj1LegIVwMmxChVXu9x0JVvvxNN6XOSvDLXwj937tDLaAYPACgQcLVDN et1IB4db+bHWPyzDTxKuanHhxCnqPofqpozsDf3M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731896AbeLTJY5 (ORCPT ); Thu, 20 Dec 2018 04:24:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:39628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730182AbeLTJYy (ORCPT ); Thu, 20 Dec 2018 04:24:54 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 C2BCF20656; Thu, 20 Dec 2018 09:24:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545297893; bh=G5b1ayP4DqY4gNdUN0MrK1ob1Adeyj75jVxspDedqZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y56jJZqEfgmvwFfS+HYB9p2tWcP0WCKqvJw+4/O/9qKlC49SFZMsNzfD9NHgFKYfQ 6V8dpxAKJyuiis4+1+dE8/FlUIhWSudWVeyJHVDA0JOuglP5kTTqwsv570Nxm84ks1 vP9ybu+IdXBsoRSxS8gVO0TJ7nWMamJqN+18LJzc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mitko Haralanov , Mike Marciniszyn , "Michael J. Ruhl" , Sasha Levin Subject: [PATCH 4.9 19/61] IB/hfi1: Remove race conditions in user_sdma send path Date: Thu, 20 Dec 2018 10:18:19 +0100 Message-Id: <20181220085844.508001228@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20181220085843.743900603@linuxfoundation.org> References: <20181220085843.743900603@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ commit 28a9a9e83ceae2cee25b9af9ad20d53aaa9ab951 upstream Packet queue state is over used to determine SDMA descriptor availablitity and packet queue request state. cpu 0 ret = user_sdma_send_pkts(req, pcount); cpu 0 if (atomic_read(&pq->n_reqs)) cpu 1 IRQ user_sdma_txreq_cb calls pq_update() (state to _INACTIVE) cpu 0 xchg(&pq->state, SDMA_PKT_Q_ACTIVE); At this point pq->n_reqs == 0 and pq->state is incorrectly SDMA_PKT_Q_ACTIVE. The close path will hang waiting for the state to return to _INACTIVE. This can also change the state from _DEFERRED to _ACTIVE. However, this is a mostly benign race. Remove the racy code path. Use n_reqs to determine if a packet queue is active or not. Cc: # 4.9.0 Reviewed-by: Mitko Haralanov Reviewed-by: Mike Marciniszyn Signed-off-by: Michael J. Ruhl Signed-off-by: Sasha Levin --- drivers/infiniband/hw/hfi1/user_sdma.c | 28 +++++++++----------------- drivers/infiniband/hw/hfi1/user_sdma.h | 7 ++++++- 2 files changed, 16 insertions(+), 19 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index 619475c7d761..4c111162d552 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -151,10 +151,6 @@ MODULE_PARM_DESC(sdma_comp_size, "Size of User SDMA completion ring. Default: 12 #define SDMA_REQ_HAVE_AHG 1 #define SDMA_REQ_HAS_ERROR 2 -#define SDMA_PKT_Q_INACTIVE BIT(0) -#define SDMA_PKT_Q_ACTIVE BIT(1) -#define SDMA_PKT_Q_DEFERRED BIT(2) - /* * Maximum retry attempts to submit a TX request * before putting the process to sleep. @@ -408,7 +404,6 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt, struct file *fp) pq->ctxt = uctxt->ctxt; pq->subctxt = fd->subctxt; pq->n_max_reqs = hfi1_sdma_comp_ring_size; - pq->state = SDMA_PKT_Q_INACTIVE; atomic_set(&pq->n_reqs, 0); init_waitqueue_head(&pq->wait); atomic_set(&pq->n_locked, 0); @@ -491,7 +486,7 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd) /* Wait until all requests have been freed. */ wait_event_interruptible( pq->wait, - (ACCESS_ONCE(pq->state) == SDMA_PKT_Q_INACTIVE)); + !atomic_read(&pq->n_reqs)); kfree(pq->reqs); kfree(pq->req_in_use); kmem_cache_destroy(pq->txreq_cache); @@ -527,6 +522,13 @@ static u8 dlid_to_selector(u16 dlid) return mapping[hash]; } +/** + * hfi1_user_sdma_process_request() - Process and start a user sdma request + * @fp: valid file pointer + * @iovec: array of io vectors to process + * @dim: overall iovec array size + * @count: number of io vector array entries processed + */ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec, unsigned long dim, unsigned long *count) { @@ -768,20 +770,12 @@ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec, } set_comp_state(pq, cq, info.comp_idx, QUEUED, 0); + pq->state = SDMA_PKT_Q_ACTIVE; /* Send the first N packets in the request to buy us some time */ ret = user_sdma_send_pkts(req, pcount); if (unlikely(ret < 0 && ret != -EBUSY)) goto free_req; - /* - * It is possible that the SDMA engine would have processed all the - * submitted packets by the time we get here. Therefore, only set - * packet queue state to ACTIVE if there are still uncompleted - * requests. - */ - if (atomic_read(&pq->n_reqs)) - xchg(&pq->state, SDMA_PKT_Q_ACTIVE); - /* * This is a somewhat blocking send implementation. * The driver will block the caller until all packets of the @@ -1526,10 +1520,8 @@ static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status) static inline void pq_update(struct hfi1_user_sdma_pkt_q *pq) { - if (atomic_dec_and_test(&pq->n_reqs)) { - xchg(&pq->state, SDMA_PKT_Q_INACTIVE); + if (atomic_dec_and_test(&pq->n_reqs)) wake_up(&pq->wait); - } } static void user_sdma_free_request(struct user_sdma_request *req, bool unpin) diff --git a/drivers/infiniband/hw/hfi1/user_sdma.h b/drivers/infiniband/hw/hfi1/user_sdma.h index 39001714f551..09dd843a13de 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.h +++ b/drivers/infiniband/hw/hfi1/user_sdma.h @@ -53,6 +53,11 @@ extern uint extended_psn; +enum pkt_q_sdma_state { + SDMA_PKT_Q_ACTIVE, + SDMA_PKT_Q_DEFERRED, +}; + struct hfi1_user_sdma_pkt_q { struct list_head list; unsigned ctxt; @@ -65,7 +70,7 @@ struct hfi1_user_sdma_pkt_q { struct user_sdma_request *reqs; unsigned long *req_in_use; struct iowait busy; - unsigned state; + enum pkt_q_sdma_state state; wait_queue_head_t wait; unsigned long unpinned; struct mmu_rb_handler *handler; -- 2.19.1