From nobody Fri Dec 19 17:23:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93229C67871 for ; Mon, 24 Oct 2022 20:40:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234709AbiJXUkQ (ORCPT ); Mon, 24 Oct 2022 16:40:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234776AbiJXUjK (ORCPT ); Mon, 24 Oct 2022 16:39:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 641E354CB4; Mon, 24 Oct 2022 11:50:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A5A5DB818CA; Mon, 24 Oct 2022 12:47:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A468C433D6; Mon, 24 Oct 2022 12:47:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666615636; bh=t/ybkTw5o5DQeKuhsC3Y22PxU+b6JRca7y1WVn2fkBM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kOPnyxYk6njV6MTx27RrzH0nl03L51e0wHVGRMSFwNp7ATvgNghboeZNOYhYt2jUG 09pjF8iWfkRvHxYeI6GYKmTVIvbIt2dLNxWLJocYW6KMRgUbNTXfA9xsqfbPfMAPJe SOKmTXx3jbt+seuYxBf9KJgnTtBs9QkFdGwu99xE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jie Hai , Zhou Wang , Vinod Koul , Sasha Levin Subject: [PATCH 5.15 296/530] dmaengine: hisilicon: Add multi-thread support for a DMA channel Date: Mon, 24 Oct 2022 13:30:40 +0200 Message-Id: <20221024113058.463935931@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jie Hai [ Upstream commit 2cbb95883c990d0002a77e13d3278913ab26ad79 ] When we get a DMA channel and try to use it in multiple threads it will cause oops and hanging the system. % echo 100 > /sys/module/dmatest/parameters/threads_per_chan % echo 100 > /sys/module/dmatest/parameters/iterations % echo 1 > /sys/module/dmatest/parameters/run [383493.327077] Unable to handle kernel paging request at virtual address dead000000000108 [383493.335103] Mem abort info: [383493.335103] ESR =3D 0x96000044 [383493.335105] EC =3D 0x25: DABT (current EL), IL =3D 32 bits [383493.335107] SET =3D 0, FnV =3D 0 [383493.335108] EA =3D 0, S1PTW =3D 0 [383493.335109] FSC =3D 0x04: level 0 translation fault [383493.335110] Data abort info: [383493.335111] ISV =3D 0, ISS =3D 0x00000044 [383493.364739] CM =3D 0, WnR =3D 1 [383493.367793] [dead000000000108] address between user and kernel address ranges [383493.375021] Internal error: Oops: 96000044 [#1] PREEMPT SMP [383493.437574] CPU: 63 PID: 27895 Comm: dma0chan0-copy2 Kdump: loaded Tainted: GO 5.17.0-rc4+ #2 [383493.457851] pstate: 204000c9 (nzCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) [383493.465331] pc : vchan_tx_submit+0x64/0xa0 [383493.469957] lr : vchan_tx_submit+0x34/0xa0 This occurs because the transmission timed out, and that's due to data race. Each thread rewrite channels's descriptor as soon as device_issue_pending is called. It leads to the situation that the driver thinks that it uses the right descriptor in interrupt handler while channels's descriptor has been changed by other thread. The descriptor which in fact reported interrupt will not be handled any more, as well as its tx->callback. That's why timeout reports. With current fixes channels' descriptor changes it's value only when it has been used. A new descriptor is acquired from vc->desc_issued queue that is already filled with descriptors that are ready to be sent. Threads have no direct access to DMA channel descriptor. In case of channel's descriptor is busy, try to submit to HW again when a descriptor is completed. In this case, vc->desc_issued may be empty when hisi_dma_start_transfer is called, so delete error reporting on this. Now it is just possible to queue a descriptor for further processing. Fixes: e9f08b65250d ("dmaengine: hisilicon: Add Kunpeng DMA engine support") Signed-off-by: Jie Hai Acked-by: Zhou Wang Link: https://lore.kernel.org/r/20220830062251.52993-4-haijie1@huawei.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/hisi_dma.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c index 9e6ce3731ca5..df6be7ca340c 100644 --- a/drivers/dma/hisi_dma.c +++ b/drivers/dma/hisi_dma.c @@ -271,7 +271,6 @@ static void hisi_dma_start_transfer(struct hisi_dma_cha= n *chan) =20 vd =3D vchan_next_desc(&chan->vc); if (!vd) { - dev_err(&hdma_dev->pdev->dev, "no issued task!\n"); chan->desc =3D NULL; return; } @@ -303,7 +302,7 @@ static void hisi_dma_issue_pending(struct dma_chan *c) =20 spin_lock_irqsave(&chan->vc.lock, flags); =20 - if (vchan_issue_pending(&chan->vc)) + if (vchan_issue_pending(&chan->vc) && !chan->desc) hisi_dma_start_transfer(chan); =20 spin_unlock_irqrestore(&chan->vc.lock, flags); @@ -441,11 +440,10 @@ static irqreturn_t hisi_dma_irq(int irq, void *data) chan->qp_num, chan->cq_head); if (FIELD_GET(STATUS_MASK, cqe->w0) =3D=3D STATUS_SUCC) { vchan_cookie_complete(&desc->vd); + hisi_dma_start_transfer(chan); } else { dev_err(&hdma_dev->pdev->dev, "task error!\n"); } - - chan->desc =3D NULL; } =20 spin_unlock(&chan->vc.lock); --=20 2.35.1