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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ben Dooks <ben.dooks@sifive.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 194/244] dmaengine: dw-axi-dmac: ignore interrupt if no descriptor
Date:   Tue, 23 Aug 2022 10:25:53 +0200
Message-Id: <20220823080105.889179972@linuxfoundation.org>
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From: Ben Dooks <ben.dooks@sifive.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@sifive.com>
Link: https://lore.kernel.org/r/20220708170153.269991-4-ben.dooks@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.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 8f765e2d7c72..48de8d2b32f2 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -1016,6 +1016,11 @@ 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);
@@ -1045,6 +1050,7 @@ 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