linux-kernel - [PATCH AUTOSEL 5.19 45/64] dmaengine: dw-axi-dmac: ignore interrupt if no descriptor

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Date:   Sun, 14 Aug 2022 11:24:18 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ben Dooks <ben.dooks@...ive.com>, Vinod Koul <vkoul@...nel.org>,
        Sasha Levin <sashal@...nel.org>, Eugeniy.Paltsev@...opsys.com,
        dmaengine@...r.kernel.org
Subject: [PATCH AUTOSEL 5.19 45/64] dmaengine: dw-axi-dmac: ignore interrupt if no descriptor

From: Ben Dooks <ben.dooks@...ive.com>

[ Upstream commit 820f5ce999d2f99961e88c16d65cd26764df0590 ]

If the channel has no descriptor and the interrupt is raised then the
kernel will OOPS. Check the result of vchan_next_desc() in the handler
axi_chan_block_xfer_complete() to avoid the error happening.

Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
Link: https://lore.kernel.org/r/20220708170153.269991-4-ben.dooks@sifive.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index 41583f01a360..a183d93bd7e2 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -1054,6 +1054,11 @@ static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
 
 	/* The completed descriptor currently is in the head of vc list */
 	vd = vchan_next_desc(&chan->vc);
+	if (!vd) {
+		dev_err(chan2dev(chan), "BUG: %s, IRQ with no descriptors\n",
+			axi_chan_name(chan));
+		goto out;
+	}
 
 	if (chan->cyclic) {
 		desc = vd_to_axi_desc(vd);
@@ -1083,6 +1088,7 @@ static void axi_chan_block_xfer_complete(struct axi_dma_chan *chan)
 		axi_chan_start_first_queued(chan);
 	}
 
+out:
 	spin_unlock_irqrestore(&chan->vc.lock, flags);
 }
 
-- 
2.35.1