Re: [Qemu-arm] [Qemu-devel] [PATCH for 2.10 21/35] arm/sysbus-fdt: fix null pointer dereference

[Eric Blake]

On 07/24/2017 04:52 PM, Eric Blake wrote:
> On 07/24/2017 04:48 PM, Philippe Mathieu-Daudé wrote:
>> On 07/24/2017 06:09 PM, Peter Maydell wrote:
>>> On 24 July 2017 at 19:27, Philippe Mathieu-Daudé <address@hidden> wrote:
>>>> Use error_report() + exit() instead of error_setg(&error_fatal).
>>>>
>>>> hw/arm/sysbus-fdt.c:322:9: warning: Array access (from variable
>>>> 'node_path') results in a null pointer dereference
>>>>      if (node_path[1]) {
>>>>          ^~~~~~~~~~~~
>>>
>>> I don't understand what this warning is trying to say.
>>> We can't get to this point with a NULL node_path,
>>> because of the previous conditional, which is using
>>> error_setg(&error_fatal).
>>
>> Ok I see, Clang is unaware than error_setg(&error_fatal) is a noreturn.
> 
> Indeed, and that's because error_setg(&error_fatal) is not in preferred
> form.
> 
>>
>> Patch dropped.
> 
> That's a shame.  Rather, we should patch this file (and others) to avoid
> all the inconsistent uses of error_setg(&error_*), to comply with the
> error.h documentation.

In other words, switching to the preferred spelling in the following files:
device_tree.c
hw/arm/sysbus-fdt.c
hw/block/fdc.c
hw/ppc/spapr_drc.c

is desirable, and has the added benefit of also silencing a Coverity
false positive.  But it should be done in terms of switching to the
preferred spelling, as it touches more instances than just the one that
shuts up Coverity.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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