Re: [Xen-devel] [PATCH v9 for Xen 4.7 3/4] libxl: enable per-VCPU parameter for RTDS

[Chong Li <lichong659@xxxxxxxxx>]

On Wed, Apr 6, 2016 at 2:30 PM, Wei Liu <wei.liu2@xxxxxxxxxx> wrote:
> On Wed, Apr 06, 2016 at 02:20:55PM -0500, Chong Li wrote:
>> On Wed, Apr 6, 2016 at 1:54 PM, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> 
>> wrote:
>> > On 06/04/16 17:41, Chong Li wrote:
>> >> On Wed, Apr 6, 2016 at 11:36 AM, Dario Faggioli
>> >> <dario.faggioli@xxxxxxxxxx> wrote:
>> >>> On Wed, 2016-04-06 at 16:38 +0100, Ian Jackson wrote:
>> >>>> Ian Jackson writes ("Re: [PATCH v9 for Xen 4.7 3/4] libxl: enable
>> >>>> per-VCPU parameter for RTDS"):
>> >>>>> Dario points out on irc that perhaps the problem is that I didn't
>> >>>>> apply 2/4.  I wasn't CC'd on 2/4, so I foolishly assumed it was a
>> >>>>> hypervisor patch (and the HV parts are already in tree).
>> >>>>>
>> >>>>> I will check my view of the xen-devel list.
>> >>>> Indeed.  With 2/4 it builds.  4/4 was also not CC'd to me.  I used a
>> >>>> copy from the list.
>> >>>>
>> >>>> I have pushed all four.
>> >>>>
>> >>> Thanks Ian!
>> >>>
>> >>> So, Chong, clearly, the build failure was not your fault (as there is
>> >>> no actual build failure), but please, always double check (even when
>> >>> sending new versions of a series) that the appropriate maintainers are
>> >>> Cc-ed... This would help limiting problems like this one we've seen
>> >>> here.
>> >>>
>> >> Yes, I'll.
>> >>
>> >> Thanks for your help on this.
>> >> Chong
>> >
>> > Yet another build failure on CentOS.
>> >
>> > xc_rt.c: In function 'xc_sched_rtds_vcpu_set':
>> > xc_rt.c:71:9: error: 'rc' may be used uninitialized in this function
>> > [-Werror=maybe-uninitialized]
>> >      int rc;
>> >          ^
>> > xc_rt.c: In function 'xc_sched_rtds_vcpu_get':
>> > xc_rt.c:105:9: error: 'rc' may be used uninitialized in this function
>> > [-Werror=maybe-uninitialized]
>> >      int rc;
>> >          ^
>> > cc1: all warnings being treated as errors
>> >
>> > In both cases, if your while loop doesn't execute (i.e. the user passes
>> > num_vcpus = 0), rc is genuinely uninialised when used at the end of the
>> > function.
>> >
>> > ~Andrew
>>
>> I see. I can do a sanity check on num_vcpus before the while loop.
>>
>
> Not sure what kind of sanity check you were thinking about. But you can
> just set rc = 0 at the beginning of each function. That semantics should
> be sensible enough. What do you think?
Yes, I can do this change. But didn't you or Dario say that rc should not be
initialized at the beginning of a function?

>
>> Do I have to re-send the whole patch series? Or maybe just something
>> like a bug fix patch?
>>
>
> Please send a patch on top of staging branch. This series has already
> been committed.
>
Sure.



-- 
Chong Li
Department of Computer Science and Engineering
Washington University in St.louis

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