From: Eric Pilmore Date: Fri, 10 Feb 2023 07:51:43 +0000 (-0800) Subject: dmaengine: ptdma: check for null desc before calling pt_cmd_callback X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=928469986171a6f763b34b039427f5667ba3fd50;p=linux.git dmaengine: ptdma: check for null desc before calling pt_cmd_callback 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 Link: https://lore.kernel.org/r/20230210075142.58253-1-epilmore@gigaio.com Signed-off-by: Vinod Koul --- 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); }