linux-kernel - [PATCH 2/3] dmaengine: dw-axi-dmac: do not print NULL LLI during error

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Date:   Fri,  8 Jul 2022 18:01:52 +0100
From:   Ben Dooks <ben.dooks@...ive.com>
To:     dmaengine@...r.kernel.org, Eugeniy.Paltsev@...opsys.com
Cc:     linux-kernel@...r.kernel.org, vkoul@...nel.org,
        Sudip Mukherjee <sudip.mukherjee@...ive.com>,
        Jude Onyenegecha <jude.onyenegecha@...ive.com>,
        Ben Dooks <ben.dooks@...ive.com>
Subject: [PATCH 2/3] dmaengine: dw-axi-dmac: do not print NULL LLI during error

During debugging we have seen an issue where axi_chan_dump_lli()
is passed a NULL LLI pointer which ends up causing an OOPS due
to trying to get fields from it. Simply print NULL LLI and exit
to avoid this.

Signed-off-by: Ben Dooks <ben.dooks@...ive.com>
---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 5 +++++
 1 file changed, 5 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 75c537153e92..d6ef5f49f281 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -1008,6 +1008,11 @@ static void axi_chan_dump_regs(struct axi_dma_chan *chan)
 static void axi_chan_dump_lli(struct axi_dma_chan *chan,
 			      struct axi_dma_hw_desc *desc)
 {
+	if (!desc->lli) {
+		dev_err(dchan2dev(&chan->vc.chan), "NULL LLI\n");
+		return;
+	}
+
 	dev_err(dchan2dev(&chan->vc.chan),
 		"SAR: 0x%llx DAR: 0x%llx LLP: 0x%llx BTS 0x%x CTL: 0x%x:%08x",
 		le64_to_cpu(desc->lli->sar),
-- 
2.35.1