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From: Dmitry Osipenko <digetx@gmail.com>
To: "Laxman Dewangan" <ldewangan@nvidia.com>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: dmaengine@vger.kernel.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v7 02/19] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list
Date: Mon,  3 Feb 2020 01:28:37 +0300
Message-ID: <20200202222854.18409-3-digetx@gmail.com> (raw)
In-Reply-To: <20200202222854.18409-1-digetx@gmail.com>

The interrupt handler puts a half-completed DMA descriptor on a free list
and then schedules tasklet to process bottom half of the descriptor that
executes client's callback, this creates possibility to pick up the busy
descriptor from the free list. Thus, let's disallow descriptor's re-use
until it is fully processed.

Cc: <stable@vger.kernel.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/dma/tegra20-apb-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 319f31d27014..4a750e29bfb5 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -281,7 +281,7 @@ static struct tegra_dma_desc *tegra_dma_desc_get(
 
 	/* Do not allocate if desc are waiting for ack */
 	list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
-		if (async_tx_test_ack(&dma_desc->txd)) {
+		if (async_tx_test_ack(&dma_desc->txd) && !dma_desc->cb_count) {
 			list_del(&dma_desc->node);
 			spin_unlock_irqrestore(&tdc->lock, flags);
 			dma_desc->txd.flags = 0;
-- 
2.24.0


  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-02 22:28 [PATCH v7 00/19] NVIDIA Tegra APB DMA driver fixes and improvements Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 01/19] dmaengine: tegra-apb: Fix use-after-free Dmitry Osipenko
2020-02-02 22:28 ` Dmitry Osipenko [this message]
2020-02-02 22:28 ` [PATCH v7 03/19] dmaengine: tegra-apb: Implement synchronization hook Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 04/19] dmaengine: tegra-apb: Prevent race conditions on channel's freeing Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 05/19] dmaengine: tegra-apb: Clean up tasklet releasing Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 06/19] dmaengine: tegra-apb: Use devm_platform_ioremap_resource Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 07/19] dmaengine: tegra-apb: Use devm_request_irq Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 08/19] dmaengine: tegra-apb: Fix coding style problems Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 09/19] dmaengine: tegra-apb: Remove unneeded initialization of tdc->config_init Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 10/19] dmaengine: tegra-apb: Remove assumptions about unavailable runtime PM Dmitry Osipenko
2020-02-04 14:51   ` Jon Hunter
2020-02-02 22:28 ` [PATCH v7 11/19] dmaengine: tegra-apb: Remove pending_sg_req checking from tdc_start_head_req Dmitry Osipenko
2020-02-04 14:53   ` Jon Hunter
2020-02-02 22:28 ` [PATCH v7 12/19] dmaengine: tegra-apb: Remove handling of unrealistic error condition Dmitry Osipenko
2020-02-04 11:52   ` Jon Hunter
2020-02-04 22:17     ` Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 13/19] dmaengine: tegra-apb: Don't stop cyclic DMA in a case of " Dmitry Osipenko
2020-02-04 12:02   ` Jon Hunter
2020-02-04 15:55     ` Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 14/19] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer Dmitry Osipenko
2020-02-06 13:50   ` Jon Hunter
2020-02-06 14:31     ` Dmitry Osipenko
2020-02-06 14:33       ` Jon Hunter
2020-02-02 22:28 ` [PATCH v7 15/19] dmaengine: tegra-apb: Clean up suspend-resume Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 16/19] dmaengine: tegra-apb: Add missing of_dma_controller_free Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 17/19] dmaengine: tegra-apb: Allow to compile as a loadable kernel module Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 18/19] dmaengine: tegra-apb: Remove MODULE_ALIAS Dmitry Osipenko
2020-02-02 22:28 ` [PATCH v7 19/19] dmaengine: tegra-apb: Support COMPILE_TEST Dmitry Osipenko

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