[Buildroot] [PATCH] package/musl: Make scheduler functions Linux-compatible

[Yann E. MORIN]

Stefan, All,

On 2019-05-14 22:03 +0200, stefan.nickl at gmail.com spake thusly:
> On Tue, 2019-05-14 at 21:38 +0200, Arnout Vandecappelle wrote:
> > 
> > On 14/05/2019 20:54, stefan.nickl at gmail.com wrote:
> > > On Tue, 2019-05-14 at 20:04 +0200, Arnout Vandecappelle wrote:
> > > >  As Thomas wrote, the patch as it is is not upstreamable since
> > > > musl
> > > > considers
> > > > this a feature.
> > > > 
> > > >  However, it is possible that Rich can be convinced to actually
> > > > read
> > > > the POSIX
> > > > spec and decide that linux behaviour is correct (except for the
> > > > fact
> > > > that it
> > > > sched_setscheduler() should return the previous scheduling policy
> > > > rather than 0,
> > > > but that can be approximated (in a racy way) by calling
> > > > sched_getscheduler()
> > > > first). So it might be worth trying to push the patch upstream.
> > > 
> > > Hi Arnout,
> > > 
> > > I think upstreaming is out of the question since Rich has actually
> > > *undone* it before 
> > > https://git.musl-libc.org/cgit/musl/commit/?id=1e21e78bf7a5
> > > 
> > > Also asked on #musl a couple days ago whether they might be willing
> > > to
> > > at least #ifdef it, and only got suggestions for application side
> > > fixes. So, no dice it seems.
> > 
> >  Yes, but has the argument "Linux does in fact implement POSIX" been
> > used already?
> 
> I haven't used that argument and I'm not aware of anyone that has.
> 
> This comes pretty close though: 
> https://github.com/MusicPlayerDaemon/MPD/issues/218
> 
> And just recently Rich managed to convince even the glibc developers of
> the opposite, so I certainly don't feel up to arguing that position ;-)
> https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c70824b9a4645c0ecd049da8cfdb2c28ae7ada23

So, if glibc is going the musl way, because Linux does not allow to
properly implement the sched_* stuff, when why do we even attempt to
implement them in musl at all?

Yes, I read the argument that "applications are broken without that",
but they are already brioken anyway because the underlyign syscalls are
unsound (from what I read in the various threads and the bugzilla).

As Thomas said, if we add this patch, we'll have to carry it ad libitum,
because there are absolutely zero chance this is upstreamed one day.

Besides, it also does not address the case for pre-built toolchains,
which leaves users out in the cold with broken applications anway.

So, as painful as it might be, I'd say no to this patch.

Regards,
Yann E. MORIN.

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