4.9-stable review patch. If anyone has any objections, please let me know.
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From: John Keeping john@metanate.com
[ 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@metanate.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/dma/pl330.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2167,13 +2167,14 @@ 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;