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 4.9-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-4.9 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-4.9/dmaengine-edma-align-the-memcpy-acnt-array-size-with-the-transfer.patch
queue-4.9/dmaengine-ti-dma-crossbar-fix-possible-race-condition-with-dma_inuse.patch