From patchwork Tue Oct 25 09:02:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 13018781 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 9ECEBC38A2D for ; Tue, 25 Oct 2022 09:05:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232203AbiJYJFG (ORCPT ); Tue, 25 Oct 2022 05:05:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231845AbiJYJEM (ORCPT ); Tue, 25 Oct 2022 05:04:12 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DEE615F927; Tue, 25 Oct 2022 02:03:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1666688624; x=1698224624; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=bZZdBBlLXwMT8tESxcHFn6Z30Buv3zSEykmc4D8zsf4=; b=mDP/WJbbgyeQqxOZ1haoJEkgQ4vBRYfpkOyQ7tCKHkL2Oz9pvfj06asB xBhTmlu71AtjiOAnihefPJ3he9TrNmAKKtxUOZnc+I/ozmVRWaLnciQQr P6/T39uUxr9CDEzlIfSmLZn2Kfgky3DSMoiW2ijcwPYpUb0hy1vMa/hSm xTLcVC/RsDQAh3UX77R9L6hsBIUwcKh70a01PDgJv3DZhOq3q2i/RtA6a vO+5IIqjqqkUIwCS7vqZKI+blpIPU7GjVYdyZb/5VSrOexO/IILxo2N5I rFTQxB3MNFYv9jgsBcF1t01sNgspTTKXKrWNpdiFaA8yvGx7PV96LuP2t w==; X-IronPort-AV: E=Sophos;i="5.95,211,1661842800"; d="scan'208";a="120221281" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 25 Oct 2022 02:03:42 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Tue, 25 Oct 2022 02:03:42 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Tue, 25 Oct 2022 02:03:40 -0700 From: Tudor Ambarus To: , , CC: , , , , , , , "Tudor Ambarus" , Subject: [PATCH v2 10/32] dmaengine: at_hdmac: Fix concurrency over the active list Date: Tue, 25 Oct 2022 12:02:44 +0300 Message-ID: <20221025090306.297886-11-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221025090306.297886-1-tudor.ambarus@microchip.com> References: <20221025090306.297886-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org The tasklet (atc_advance_work()) did not held the channel lock when retrieving the first active descriptor, causing concurrency problems if issue_pending() was called in between. If issue_pending() was called exactly after the lock was released in the tasklet (atc_advance_work()), atc_chain_complete() could complete a descriptor for which the controller has not yet raised an interrupt. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ --- drivers/dma/at_hdmac.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 0fb44f622d35..b53a9fc15dd9 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -462,8 +462,6 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) if (!atc_chan_is_cyclic(atchan)) dma_cookie_complete(txd); - /* Remove transfer node from the active list. */ - list_del_init(&desc->desc_node); spin_unlock_irqrestore(&atchan->lock, flags); dma_descriptor_unmap(txd); @@ -495,6 +493,7 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) */ static void atc_advance_work(struct at_dma_chan *atchan) { + struct at_desc *desc; unsigned long flags; dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n"); @@ -502,9 +501,12 @@ static void atc_advance_work(struct at_dma_chan *atchan) spin_lock_irqsave(&atchan->lock, flags); if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list)) return spin_unlock_irqrestore(&atchan->lock, flags); - spin_unlock_irqrestore(&atchan->lock, flags); - atc_chain_complete(atchan, atc_first_active(atchan)); + desc = atc_first_active(atchan); + /* Remove the transfer node from the active list. */ + list_del_init(&desc->desc_node); + spin_unlock_irqrestore(&atchan->lock, flags); + atc_chain_complete(atchan, desc); /* advance work */ spin_lock_irqsave(&atchan->lock, flags);