Commit c33ee130 authored Feb 09, 2020 by Dmitry Osipenko Committed by Vinod Koul Feb 25, 2020

dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list



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.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200209163356.6439-3-digetx@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>

parent 94788af4

drivers/dma/tegra20-apb-dma.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

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