linux-kernel - [PATCH 5.4 11/37] dmaengine: dw-edma: Fix crash on loading/unloading driver

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Date:   Thu, 20 May 2021 11:22:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Vinod Koul <vkoul@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 11/37] dmaengine: dw-edma: Fix crash on loading/unloading driver

From: Gustavo Pimentel <Gustavo.Pimentel@...opsys.com>

[ Upstream commit e970dcc4bd8e0a1376e794fc81d41d0fc98262dd ]

When the driver is compiled as a module and loaded if we try to unload
it, the Kernel shows a crash log. This Kernel crash is due to the
dma_async_device_unregister() call done after deleting the channels,
this patch fixes this issue.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
Link: https://lore.kernel.org/r/4aa850c035cf7ee488f1d3fb6dee0e37be0dce0a.1613674948.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 31577316f80b..afbd1a459019 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -910,22 +910,21 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 	/* Power management */
 	pm_runtime_disable(dev);
 
+	/* Deregister eDMA device */
+	dma_async_device_unregister(&dw->wr_edma);
 	list_for_each_entry_safe(chan, _chan, &dw->wr_edma.channels,
 				 vc.chan.device_node) {
-		list_del(&chan->vc.chan.device_node);
 		tasklet_kill(&chan->vc.task);
+		list_del(&chan->vc.chan.device_node);
 	}
 
+	dma_async_device_unregister(&dw->rd_edma);
 	list_for_each_entry_safe(chan, _chan, &dw->rd_edma.channels,
 				 vc.chan.device_node) {
-		list_del(&chan->vc.chan.device_node);
 		tasklet_kill(&chan->vc.task);
+		list_del(&chan->vc.chan.device_node);
 	}
 
-	/* Deregister eDMA device */
-	dma_async_device_unregister(&dw->wr_edma);
-	dma_async_device_unregister(&dw->rd_edma);
-
 	/* Turn debugfs off */
 	dw_edma_v0_core_debugfs_off();
 
-- 
2.30.2