4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: John Keeping <john@xxxxxxxxxxxx>
[ Upstream commit e49756544a21f5625b379b3871d27d8500764670 ]
In pl330_update() when checking if a channel has been aborted, the
channel's lock is not taken, only the overall pl330_dmac lock. But in
pl330_terminate_all() the aborted flag (req_running==-1) is set under
the channel lock and not the pl330_dmac lock.
With threaded interrupts, this leads to a potential race:
pl330_terminate_all pl330_update
------------------- ------------
lock channel
entry
lock pl330
_stop channel
unlock pl330
lock pl330
check req_running != -1
req_running = -1
_start channel
Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/pl330.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2132,13 +2132,14 @@ static int pl330_terminate_all(struct dm
pm_runtime_get_sync(pl330->ddma.dev);
spin_lock_irqsave(&pch->lock, flags);
+
spin_lock(&pl330->lock);
_stop(pch->thread);
- spin_unlock(&pl330->lock);
-
pch->thread->req[0].desc = NULL;
pch->thread->req[1].desc = NULL;
pch->thread->req_running = -1;
+ spin_unlock(&pl330->lock);
+
power_down = pch->active;
pch->active = false;
