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

[Ludovic Desroches]

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 
Acked-by: Ludovic Desroches 

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

[Nicolas Ferre]

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 
---
 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