From patchwork Sat Aug 20 12:57:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 12949687 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2527EC25B08 for ; Sat, 20 Aug 2022 13:05:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wrdOohBEEuJwiI2qnV1V+l1unWHJ8UUgBU2SaT8xjcU=; b=U2XiMwD8roN7Wl zlvB47gfN2wnpqYQ56DD893G5gXUfYsWUiQPXGXBaVWOWdCpUraakCHr2kDUMhhmEHmKvi7AyPdRB 72Ugd2Pi6AF6R+tQfrHUIKGh/bnFsKw1X9eU5+IRkvSD+rGt8vEPxmulGcGDFbarXSEoeYwO5h9/l s6Qn2JzPD2Hex2eekVDaedG5jSbezD5fmbomeYSMU7t+quK4ImqeHGemI1gpHJW5iSoARLIQo7G7C 3gyM6R4NZiKaIeMOAE7hj9eJ/yV5CjBEmRP5ASBZOPhIEqK8Af0UMxlXDBsV3F6BqRNiLeVXysRpq Mv9dUx2KfyFadndl/GPA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oPO91-00AFrL-57; Sat, 20 Aug 2022 13:04:07 +0000 Received: from esa.microchip.iphmx.com ([68.232.154.123]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oPO3P-00ACfY-Lb for linux-arm-kernel@lists.infradead.org; Sat, 20 Aug 2022 12:58:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1661000299; x=1692536299; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PCoOcNi4gHsugNwjMnoPFdo3B9vCHVSc5ivgIMrs5J0=; b=TfuYDM0oD3vUr8EQPdZ3Bo4zcUqvxg11SDQPfkr1bdfpXeVaK1FirLF3 n07zeApn/RpyXSDSSgpL9n9nTJsykE/M0BXp7WF2b5IMOIymgR00MzVF+ MzQIv1agaxv8X+QMjFcMTS01+zmtC/GwpUunWJoKLBW5Ld+C4A7ggA3KM tCSL/oTKblUP5Usi4lH1svcqIHbVLuGuhoXiqb+PgatiPj1Y7Y7Kr57ZB G5wJm6U/vOu5wphod/J1+vSQHJd/VPNeC96WLJawCWyZtxuvwk7Wa0rLm WVTWhaGkpZlEay1m+f4BnK0yoGjCl2ohrFKZpBv45Y4v7e/rUIXlcjoSy A==; X-IronPort-AV: E=Sophos;i="5.93,251,1654585200"; d="scan'208";a="109911541" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 20 Aug 2022 05:58:18 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.87.72) by chn-vm-ex02.mchp-main.com (10.10.87.72) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Sat, 20 Aug 2022 05:58:18 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Sat, 20 Aug 2022 05:58:15 -0700 From: Tudor Ambarus To: , , , Subject: [PATCH 16/33] dmaengine: at_hdmac: Fix concurrency over the active list Date: Sat, 20 Aug 2022 15:57:00 +0300 Message-ID: <20220820125717.588722-17-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220820125717.588722-1-tudor.ambarus@microchip.com> References: <20220820125717.588722-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220820_055819_812151_E1293F46 X-CRM114-Status: GOOD ( 11.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tudor.ambarus@microchip.com, linux-kernel@vger.kernel.org, maciej.sosnowski@intel.com, mripard@kernel.org, torfl6749@gmail.com, ludovic.desroches@microchip.com, stable@vger.kernel.org, dmaengine@vger.kernel.org, dan.j.williams@intel.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The tasklet 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_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 Cc: stable@vger.kernel.org Signed-off-by: Tudor Ambarus 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 c2b3d7b63920..635c3be74399 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -897,8 +897,6 @@ 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); @@ -930,6 +928,7 @@ 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->dma_chan), "advance_work\n"); @@ -937,9 +936,12 @@ 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);