Re: Coverity complaints about Remus in xen-unstable

[Hongyang Yang <yanghy@cn.fujitsu.com>]

在 10/01/2014 11:32 PM, Ian Jackson 写道:
> scan-admin@coverity.com writes ("New Defects reported by Coverity Scan for XenProject"):
>> Please find the latest report on new defect(s) introduced to XenProject found with Coverity Scan.
> ...
>> ** CID 1242320:  Uninitialized scalar variable  (UNINIT)
>> /tools/libxl/libxl.c: 859 in libxl_domain_remus_start()
>
> This is a failure to set rc on some of the error paths.  It is not a
> big problem, but it is a bug which should be fixed, in
> libxl_domain_remus_start.
>
> Yang Hongyang, could you prepare a patch to fix all the error exit
> paths from this function to correctly set rc ?  Thanks.
>
>
> Then there are also a lot like this:
>
>> ** CID 1242321:  Unused value  (UNUSED_VALUE)
>> /tools/libxl/libxl_remus_device.c: 216 in all_devices_setup_cb()
>
> These are all:
>
>>>>>      Pointer "gc" returned by "libxl__ao_inprogress_gc(ao)" is never used.
>
> This is because a lot of functions were introduced which say
>      STATE_AO_GC(something)
> but do not happen to use the gc.  This is actually perfectly normal
> in libxl.  And the STATE_AO_GC macro says:
>      libxl__gc *const gc __attribute__((unused)) = libxl__ao_inprogress_gc(ao)
> So I think this is some kind of failure by Coverity.
>
> Weirdly, although many of these uses (eg, all_devices_setup_cb at
> libxl_remus_device.c:212) are in functions which do not use the
> defined `ao' variable either, and ao is _not_ marked ok-to-be-unused,
> Coverity hasn't complained about that.
>
> Andrew Cooper, as our Coverity modelling expert, can you comment ?
>
>
> I don't think there is actually anything wrong with having STATE_AO_GC
> used when not needed.  It will reduce noise in future if code is added
> which needs it, and in the meantime it's harmless.  So I think it
> would probably be better if STATE_AO_GC declared ao
> __attribute__((unused)) as well.
>
> Yang Hongyang, supposing my comaintainers agree, would you care to
> write a patch to do this ?

Sure, I saw that Andrew has already post the patch, is there anything
else that I can do to help on this?

>
>
> Thanks,
> Ian.
> .
>

-- 
Thanks,
Yang.

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