From: Eric Pilmore epilmore@gigaio.com
[ Upstream commit 928469986171a6f763b34b039427f5667ba3fd50 ]
Resolves a panic that can occur on AMD systems, typically during host shutdown, after the PTDMA driver had been exercised. The issue was the pt_issue_pending() function is mistakenly assuming that there will be at least one descriptor in the Submitted queue when the function is called. However, it is possible that both the Submitted and Issued queues could be empty, which could result in pt_cmd_callback() being mistakenly called with a NULL pointer. Ref: Bugzilla Bug 216856.
Fixes: 6fa7e0e836e2 ("dmaengine: ptdma: fix concurrency issue with multiple dma transfer") Signed-off-by: Eric Pilmore epilmore@gigaio.com Link: https://lore.kernel.org/r/20230210075142.58253-1-epilmore@gigaio.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/ptdma/ptdma-dmaengine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma/ptdma/ptdma-dmaengine.c b/drivers/dma/ptdma/ptdma-dmaengine.c index cc22d162ce250..1aa65e5de0f3a 100644 --- a/drivers/dma/ptdma/ptdma-dmaengine.c +++ b/drivers/dma/ptdma/ptdma-dmaengine.c @@ -254,7 +254,7 @@ static void pt_issue_pending(struct dma_chan *dma_chan) spin_unlock_irqrestore(&chan->vc.lock, flags);
/* If there was nothing active, start processing */ - if (engine_is_idle) + if (engine_is_idle && desc) pt_cmd_callback(desc, 0); }