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

From: Greg Kroah-Hartman
Date: Thu May 20 2021 - 05:32:24 EST


From: Gustavo Pimentel <Gustavo.Pimentel@xxxxxxxxxxxx>

[ 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@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/4aa850c035cf7ee488f1d3fb6dee0e37be0dce0a.1613674948.git.gustavo.pimentel@xxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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