The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
06988949df8c ("dmaengine: at_hdmac: Fix concurrency over descriptor") 078a6506141a ("dmaengine: at_hdmac: Fix deadlocks")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 06988949df8c3007ad82036d3606d8ae72ed9000 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus tudor.ambarus@microchip.com Date: Tue, 25 Oct 2022 12:02:42 +0300 Subject: [PATCH] dmaengine: at_hdmac: Fix concurrency over descriptor
The descriptor was added to the free_list before calling the callback, which could result in reissuing of the same descriptor and calling of a single callback for both. Move the decriptor to the free list after the callback is invoked.
Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin peda@axentia.se Signed-off-by: Tudor Ambarus tudor.ambarus@microchip.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se... Acked-by: Nicolas Ferre nicolas.ferre@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.co... Link: https://lore.kernel.org/r/20221025090306.297886-9-tudor.ambarus@microchip.co... Signed-off-by: Vinod Koul vkoul@kernel.org
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index f1e6fa6af6c2..2012ecc57826 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -469,11 +469,8 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) desc->memset_buffer = false; }
- /* move children to free_list */ - list_splice_init(&desc->tx_list, &atchan->free_list); - /* move myself to free_list */ - list_move(&desc->desc_node, &atchan->free_list); - + /* Remove transfer node from the active list. */ + list_del_init(&desc->desc_node); spin_unlock_irqrestore(&atchan->lock, flags);
dma_descriptor_unmap(txd); @@ -483,6 +480,13 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) dmaengine_desc_get_callback_invoke(txd, NULL);
dma_run_dependencies(txd); + + spin_lock_irqsave(&atchan->lock, flags); + /* move children to free_list */ + list_splice_init(&desc->tx_list, &atchan->free_list); + /* add myself to free_list */ + list_add(&desc->desc_node, &atchan->free_list); + spin_unlock_irqrestore(&atchan->lock, flags); }
/**