Messages in this thread | | | Subject | Re: [qemu] boot failed: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 | From | Dave Jiang <> | Date | Mon, 6 Jul 2020 08:26:56 -0700 |
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On 7/6/2020 8:24 AM, Arnd Bergmann wrote: > On Mon, Jul 6, 2020 at 5:01 PM Dave Jiang <dave.jiang@intel.com> wrote: >> On 7/6/2020 5:53 AM, Arnd Bergmann wrote: >>> On Mon, Jul 6, 2020 at 1:03 PM Naresh Kamboju <naresh.kamboju@linaro.org> wrote: >> >> 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. > > No. IS_ERR_OR_NULL() is almost always a mistake. A function should either > return NULL on error, or it should return an error code, but should not be > able to return either.
Fair enough.
> > Have you checked all the other 'return NULL' statements in your patch to > ensure that they never return error pointers?
Yeah I looked over the rest of them. The ones that are returning NULL as far as I can tell are expected to return NULL.
> > Arnd >
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