This is a note to let you know that I've just added the patch titled dmaengine: ti-dma-crossbar: Fix possible race condition with dma_inuse to the 4.13-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-ti-dma-crossbar-fix-possible-race-condition-with-dma_inuse.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 2ccb4837c938357233a0b8818e3ca3e58242c952 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi <peter.ujfalusi@xxxxxx> Date: Thu, 21 Sep 2017 14:35:32 +0300 Subject: dmaengine: ti-dma-crossbar: Fix possible race condition with dma_inuse From: Peter Ujfalusi <peter.ujfalusi@xxxxxx> commit 2ccb4837c938357233a0b8818e3ca3e58242c952 upstream. When looking for unused xbar_out lane we should also protect the set_bit() call with the same mutex to protect against concurrent threads picking the same ID. Fixes: ec9bfa1e1a796 ("dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr") Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx> Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/dma/ti-dma-crossbar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/dma/ti-dma-crossbar.c +++ b/drivers/dma/ti-dma-crossbar.c @@ -262,13 +262,14 @@ static void *ti_dra7_xbar_route_allocate mutex_lock(&xbar->mutex); map->xbar_out = find_first_zero_bit(xbar->dma_inuse, xbar->dma_requests); - mutex_unlock(&xbar->mutex); if (map->xbar_out == xbar->dma_requests) { + mutex_unlock(&xbar->mutex); dev_err(&pdev->dev, "Run out of free DMA requests\n"); kfree(map); return ERR_PTR(-ENOMEM); } set_bit(map->xbar_out, xbar->dma_inuse); + mutex_unlock(&xbar->mutex); map->xbar_in = (u16)dma_spec->args[0]; Patches currently in stable-queue which might be from peter.ujfalusi@xxxxxx are queue-4.13/dmaengine-edma-align-the-memcpy-acnt-array-size-with-the-transfer.patch queue-4.13/dmaengine-ti-dma-crossbar-fix-possible-race-condition-with-dma_inuse.patch