This is a note to let you know that I've just added the patch titled dmaengine: at_xdmac: Fix concurrency over xfers_list to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dmaengine-at_xdmac-fix-concurrency-over-xfers_list.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 18deddea9184b62941395889ff7659529c877326 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> Date: Wed, 15 Dec 2021 13:01:10 +0200 Subject: dmaengine: at_xdmac: Fix concurrency over xfers_list From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> commit 18deddea9184b62941395889ff7659529c877326 upstream. Since tx_submit can be called from a hard IRQ, xfers_list must be protected with a lock to avoid concurency on the list's elements. Since at_xdmac_handle_cyclic() is called from a tasklet, spin_lock_irq is enough to protect from a hard IRQ. Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver") Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211215110115.191749-8-tudor.ambarus@xxxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/dma/at_xdmac.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1619,14 +1619,17 @@ static void at_xdmac_handle_cyclic(struc struct at_xdmac_desc *desc; struct dma_async_tx_descriptor *txd; - if (!list_empty(&atchan->xfers_list)) { - desc = list_first_entry(&atchan->xfers_list, - struct at_xdmac_desc, xfer_node); - txd = &desc->tx_dma_desc; - - if (txd->flags & DMA_PREP_INTERRUPT) - dmaengine_desc_get_callback_invoke(txd, NULL); + spin_lock_irq(&atchan->lock); + if (list_empty(&atchan->xfers_list)) { + spin_unlock_irq(&atchan->lock); + return; } + desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, + xfer_node); + spin_unlock_irq(&atchan->lock); + txd = &desc->tx_dma_desc; + if (txd->flags & DMA_PREP_INTERRUPT) + dmaengine_desc_get_callback_invoke(txd, NULL); } static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) Patches currently in stable-queue which might be from tudor.ambarus@xxxxxxxxxxxxx are queue-5.15/dmaengine-at_xdmac-fix-concurrency-over-xfers_list.patch queue-5.15/tty-serial-atmel-call-dma_async_issue_pending.patch queue-5.15/dmaengine-at_xdmac-fix-lld-view-setting.patch queue-5.15/dmaengine-at_xdmac-fix-at_xdmac_lld-struct-definition.patch queue-5.15/dmaengine-at_xdmac-print-debug-message-after-realeasing-the-lock.patch queue-5.15/dmaengine-at_xdmac-start-transfer-for-cyclic-channels-in-issue_pending.patch queue-5.15/dmaengine-at_xdmac-don-t-start-transactions-at-tx_submit-level.patch queue-5.15/tty-serial-atmel-check-return-code-of-dmaengine_subm.patch queue-5.15/crypto-atmel-aes-reestablish-the-correct-tfm-context.patch