Re: [Xen-devel] [PATCH] fix uninitialized variable error in do_poll()

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Oct 05, 2018 at 05:22:29AM -0600, Jan Beulich wrote:
> >>> On 05.10.18 at 12:28, <wei.liu2@xxxxxxxxxx> wrote:
> > On Fri, Oct 05, 2018 at 04:12:10AM -0600, Jan Beulich wrote:
> >> Now that CONFIG_HVM can (and should) be turned off for the shim, gcc 8.2
> >> apparently is no longer sure that "port" is indeed initialized at
> >> 
> >>     if ( sched_poll->nr_ports == 1 )
> >>         v->poll_evtchn = port;
> >> 
> >> It doesn't look to be impossible for the compiler to prove it is not,
> >> but we also can't rely on that to be the case. Add an initializer.
> >> 
> >> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> > 
> > TBH I fail to see how CONFIG_HVM would affect do_poll. Also there is
> > already build test with gcc 8.2 which never discovered the issue you
> > described.
> 
> I can't explain the sudden diagnostic too (without taking apart what
> exactly the compiler does), but the same config (just with HVM=y)
> built fine before. Without any further insight (which I don't think is
> worth the time) I don't see how I could improve the description.

Oh well.

Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>


> 
> Jan
> 
> 

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