[PATCH 4.4 16/91] dmaengine: at_hdmac: fix module unloading

From: Greg Kroah-Hartman
Date: Tue Dec 11 2018 - 10:46:28 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Richard Genoud <richard.genoud@xxxxxxxxx>

commit 77e75fda94d2ebb86aa9d35fb1860f6395bf95de upstream.

of_dma_controller_free() was not called on module onloading.
This lead to a soft lockup:
watchdog: BUG: soft lockup - CPU#0 stuck for 23s!
Modules linked in: at_hdmac [last unloaded: at_hdmac]
when of_dma_request_slave_channel() tried to call ofdma->of_dma_xlate().

Cc: stable@xxxxxxxxxxxxxxx
Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
Acked-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
Signed-off-by: Richard Genoud <richard.genoud@xxxxxxxxx>
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/dma/at_hdmac.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -2152,6 +2152,8 @@ static int at_dma_remove(struct platform
struct resource *io;

+ if (pdev->dev.of_node)
+ of_dma_controller_free(pdev->dev.of_node);