Re: [qemu] boot failed: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

[Naresh Kamboju]

> Arnd,
> I'm looking at the pl001_dma_probe(), I think we could make it more robust if it
> uses IS_ERR_OR_NULL(chan) instead of IS_ERR(). Should I send a patch for it? I
> suppose looking at the comment header for dma_request_chan() it does say return
> chan ptr or error ptr. Sorry I missed that.
>
>
> Vinod,
> It looks like the only fix for dmaengine for the patch is where Arnd pointed out
> as far as I can tell after auditing it. Let me know how you want to handle this.
> Thanks!

This proposed fix patch applied on top of linux next ( 20200706 tag )
and boot test PASS.

The reported problem got fixed.

Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>

>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 0d6529eff66f..48e159e83cf5 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -852,7 +852,7 @@ struct dma_chan *dma_request_chan(struct device *dev, const
> char *name)
>          mutex_lock(&dma_list_mutex);
>          if (list_empty(&dma_device_list)) {
>                  mutex_unlock(&dma_list_mutex);
> -               return NULL;
> +               return ERR_PTR(-ENODEV);
>          }
>
>          list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {

ref:
https://lkft.validation.linaro.org/scheduler/job/1542630#L510

-- 
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https://lkft.linaro.org