Patchwork [1/3] dmaengine: at_xdmac: remove BUG_ON macro in tasklet

login
register
mail settings
Submitter Nicolas Ferre
Date Feb. 5, 2019, 11:03 a.m.
Message ID <324b91c71a148a7694d28d9b8b4364095d9b0ebe.1549364323.git.nicolas.ferre@microchip.com>
Download mbox | patch
Permalink /patch/718249/
State New
Headers show

Comments

Nicolas Ferre - Feb. 5, 2019, 11:03 a.m.
Even if this case shouldn't happen when controller is properly programmed,
it's still better to avoid dumping a kernel Oops for this.
As the sequence may happen only for debugging purposes, log the error and
just finish the tasklet call.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
 drivers/dma/at_xdmac.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
Ludovic Desroches - Feb. 5, 2019, 12:30 p.m.
On Tue, Feb 05, 2019 at 12:03:41PM +0100, Nicolas Ferre wrote:
> Even if this case shouldn't happen when controller is properly programmed,
> it's still better to avoid dumping a kernel Oops for this.
> As the sequence may happen only for debugging purposes, log the error and
> just finish the tasklet call.
> 
> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

Thanks

> ---
>  drivers/dma/at_xdmac.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
> index fe69dccfa0c0..37a269420435 100644
> --- a/drivers/dma/at_xdmac.c
> +++ b/drivers/dma/at_xdmac.c
> @@ -1606,7 +1606,11 @@ static void at_xdmac_tasklet(unsigned long data)
>  					struct at_xdmac_desc,
>  					xfer_node);
>  		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
> -		BUG_ON(!desc->active_xfer);
> +		if (!desc->active_xfer) {
> +			dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
> +			spin_unlock_bh(&atchan->lock);
> +			return;
> +		}
>  
>  		txd = &desc->tx_dma_desc;
>  
> -- 
> 2.17.1
>

Patch

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index fe69dccfa0c0..37a269420435 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1606,7 +1606,11 @@  static void at_xdmac_tasklet(unsigned long data)
 					struct at_xdmac_desc,
 					xfer_node);
 		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
-		BUG_ON(!desc->active_xfer);
+		if (!desc->active_xfer) {
+			dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
+			spin_unlock_bh(&atchan->lock);
+			return;
+		}
 
 		txd = &desc->tx_dma_desc;