From: Tudor Ambarus tudor.ambarus@microchip.com
commit 03ed9ba357cc78116164b90b87f45eacab60b561 upstream.
The tasklet (atc_advance_work()) did not held the channel lock when retrieving the first active descriptor, causing concurrency problems if issue_pending() was called in between. If issue_pending() was called exactly after the lock was released in the tasklet (atc_advance_work()), atc_chain_complete() could complete a descriptor for which the controller has not yet raised an interrupt.
Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin peda@axentia.se Signed-off-by: Tudor Ambarus tudor.ambarus@microchip.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se... Acked-by: Nicolas Ferre nicolas.ferre@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.co... Link: https://lore.kernel.org/r/20221025090306.297886-11-tudor.ambarus@microchip.c... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/dma/at_hdmac.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -443,8 +443,6 @@ atc_chain_complete(struct at_dma_chan *a if (!atc_chan_is_cyclic(atchan)) dma_cookie_complete(txd);
- /* Remove transfer node from the active list. */ - list_del_init(&desc->desc_node); spin_unlock_irqrestore(&atchan->lock, flags);
dma_descriptor_unmap(txd); @@ -476,6 +474,7 @@ atc_chain_complete(struct at_dma_chan *a */ static void atc_advance_work(struct at_dma_chan *atchan) { + struct at_desc *desc; unsigned long flags;
dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n"); @@ -483,9 +482,12 @@ static void atc_advance_work(struct at_d spin_lock_irqsave(&atchan->lock, flags); if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list)) return spin_unlock_irqrestore(&atchan->lock, flags); - spin_unlock_irqrestore(&atchan->lock, flags);
- atc_chain_complete(atchan, atc_first_active(atchan)); + desc = atc_first_active(atchan); + /* Remove the transfer node from the active list. */ + list_del_init(&desc->desc_node); + spin_unlock_irqrestore(&atchan->lock, flags); + atc_chain_complete(atchan, desc);
/* advance work */ spin_lock_irqsave(&atchan->lock, flags);