[libvirt PATCH] qemu: Fix domain ID allocation
Daniel P. Berrangé
berrange at redhat.com
Mon Feb 3 10:31:12 UTC 2020
On Fri, Jan 31, 2020 at 04:33:50PM +0100, Michal Privoznik wrote:
> On 1/31/20 3:43 PM, Ján Tomko wrote:
> > The rewrite to use GLib's atomic ops functions changed the behavior
> > of virAtomicIntInc - before it returned the pre-increment value.
> >
> > Most of the callers using its value were adjusted, but the one
> > in qemuDriverAllocateID was not. If libvirtd would reconnect to
> > a running domain during startup, the next started domain would get
> > the same ID:
> >
> > $ virsh list
> > Id Name State
> > --------------------------
> > 1 f28live running
> > 1 f28live1 running
> >
> > Use the g_atomic_add function directly (as recommended in viratomic.h)
> > and add 1 to the result.
> >
> > This also restores the usual numbering from 1 instead of 0.
> >
> > Signed-off-by: Ján Tomko <jtomko at redhat.com>
> > Fixes: 7b9645a7d127a374b8d1c83fdf9789706dbab2c9
> > ---
> > src/qemu/qemu_conf.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> > index e5051027fc..0b119cbe78 100644
> > --- a/src/qemu/qemu_conf.c
> > +++ b/src/qemu/qemu_conf.c
> > @@ -1858,7 +1858,7 @@ qemuSetUnprivSGIO(virDomainDeviceDefPtr dev)
> > int qemuDriverAllocateID(virQEMUDriverPtr driver)
> > {
> > - return virAtomicIntInc(&driver->lastvmid);
> > + return g_atomic_int_add(&driver->lastvmid, 1) + 1;
> > }
> >
>
> Does it makes sense to replace all virAtomic with g_atomic or do we still
> pretend that we care about client library and we don't crash on OOM in it?
We explicitly abort-on-OOM *everywhere*, the moment we started using
g_new for VIR_ALLOC, and that includs the client library.
Regards,
Daniel
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