On Wed, Jan 25, 2023 at 15:58:25 +0000, Daniel P. Berrangé wrote:
> On Wed, Jan 11, 2023 at 12:34:29PM +0000, Daniel P. Berrangé wrote:
> > On Tue, Jan 10, 2023 at 10:55:36PM -0500, Emilio Cota wrote:
> > > qemu-user can hang in a multi-threaded fork. One common
> > > reason is that when creating a TB, between fork and exec
> > > we manipulate a GTree whose memory allocator (GSlice) is
> > > not fork-safe.
> >
> > BTW, I just checked latest glib status
> >
> > https://gitlab.gnome.org/GNOME/glib/-/issues/1079
> >
> > it appears they're pretty close to deciding to delete the
> > GSlice impl and always use system malloc.
>
> They have now merged the code to delete the GSlice custom allocator.
>
> So glib >= 2.76.0 should not exhibit a hang
>
> > So if we do take this patch series it'll hopefully be a time
> > limited thing to carry.
>
> So the question is whether the issue is critical enough that we want
> to carry a workaround for a while, vs telling users to upgrade to
> newer glib (once 2.76 actually gets released)
That is great news!
Since this is a correctness issue, I think we should ship with qtree
and use it when configuring with glib <2.76.0. For later glib versions
we would just use gtree, e.g. via typedef + inline functions.
Once the minimum glib required by the configure script is >= 2.76.0,
then we'd remove qtree.
If that sounds like a good plan, I can send a v2.
Thanks,
Emilio
