Re: [PATCH] dmaengine: at_hdmac: fix module unloading

From: Ludovic Desroches <ludovic.desroches@microchip.com>
To: Richard Genoud <richard.genoud@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Vinod Koul <vkoul@kernel.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	Mario Forner <m.forner@be4energy.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-serial@vger.kernel.org>, <stable@vger.kernel.org>
Subject: Re: [PATCH] dmaengine: at_hdmac: fix module unloading
Date: Thu, 29 Nov 2018 14:52:59 +0100	[thread overview]
Message-ID: <20181129135259.nhzx5wvpc6kxosto@M43218.corp.atmel.com> (raw)
In-Reply-To: <20181127160635.11836-2-richard.genoud@gmail.com>

On Tue, Nov 27, 2018 at 05:06:35PM +0100, Richard Genoud wrote:
> of_dma_controller_free() was not called on module onloading.

s/onloading/unloading

> 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@vger.kernel.org
> Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>

Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Thanks

Ludovic

> ---
>  drivers/dma/at_hdmac.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index 1b7f0ca0d5cd..01d936c9fe89 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -2006,6 +2006,8 @@ static int at_dma_remove(struct platform_device *pdev)
>  	struct resource		*io;
>  
>  	at_dma_off(atdma);
> +	if (pdev->dev.of_node)
> +		of_dma_controller_free(pdev->dev.of_node);
>  	dma_async_device_unregister(&atdma->dma_common);
>  
>  	dma_pool_destroy(atdma->memset_pool);