Re: bluez SEGV in current master

[Joakim Tjernlund <Joakim.Tjernlund@infinera.com>]

On Wed, 2023-06-14 at 09:53 -0700, Luiz Augusto von Dentz wrote:
> Hi Joakim,
>
> On Wed, Jun 14, 2023 at 9:32 AM Joakim Tjernlund
> <Joakim.Tjernlund@infinera.com> wrote:
> >
> > On Wed, 2023-06-14 at 09:25 -0700, Luiz Augusto von Dentz wrote:
> > > Hi Joakim,
> > >
> > > On Wed, Jun 14, 2023 at 5:36 AM Joakim Tjernlund
> > > <Joakim.Tjernlund@infinera.com> wrote:
> > > >
> > > > commit bap: Add broadcast source support, 3030883, in bluez.git
> > > >
> > > > A co-worker see this SEGV when connecting a headset:
> > > >
> > > > Jun 13 13:38:15 systemd-coredump[3941]: Process 1897 (bluetoothd) of user 0 dumped core.
> > > >                                         Module bluetoothd without build-id.
> > > >                                         #0  0x0000556bea93277a a2dp_resume_complete (bluetoothd + 0x3e77a)
> > > >                                         #1  0x0000556bea9210a2 finalize_resume (bluetoothd + 0x2d0a2)
> > > >                                         #2  0x0000556bea92afaf avdtp_start_resp (bluetoothd + 0x36faf)
> > > >                                         #6  0x0000556bea9dcc85 mainloop_run (bluetoothd + 0xe8c85)
> > > >                                         #7  0x0000556bea9dd0dc mainloop_run_with_signal (bluetoothd + 0xe90dc)
> > > >                                         #8  0x0000556bea91a4ef main (bluetoothd + 0x264ef)
> > > >                                         #11 0x0000556bea91ace1 _start (bluetoothd + 0x26ce1)
> > > > Jun 13 13:38:15 systemd[1]: bluetooth.service: Main process exited, code=dumped, status=11/SEGV
> > > >
> > > >
> > > > Crash seems to be at:
> > > >
> > > > 342     static void a2dp_resume_complete(struct avdtp *session, int err,
> > > > 343                                                             void *user_data)
> > > > 344     {
> > > > 345             struct media_owner *owner = user_data;
> > > > 346             struct media_request *req = owner->pending;
> > > > 347             struct media_transport *transport = owner->transport;
> > > > 348             struct a2dp_sep *sep = media_endpoint_get_sep(transport->endpoint);
> > > >
> > > > A good start(but does NOT fix the problem) might be:
> > > >
> > > > --- bluez-9999/profiles/audio/transport.c.org   2023-06-13 18:38:14.542137531 +0200
> > > > +++ bluez-9999/profiles/audio/transport.c       2023-06-13 18:48:32.542527882 +0200
> > > > @@ -345,7 +345,7 @@
> > > >         struct media_owner *owner = user_data;
> > > >         struct media_request *req = owner->pending;
> > > >         struct media_transport *transport = owner->transport;
> > > > -       struct a2dp_sep *sep = media_endpoint_get_sep(transport->endpoint);
> > > > +       struct a2dp_sep *sep;
> > > >         struct avdtp_stream *stream;
> > > >         int fd;
> > > >         uint16_t imtu, omtu;
> > > > @@ -355,7 +355,10 @@
> > > >
> > > >         if (err)
> > > >                 goto fail;
> > > > +       if (!transport)
> > > > +               goto fail;
> > > >
> > > > +       sep = media_endpoint_get_sep(transport->endpoint);
> > > >         stream = a2dp_sep_get_stream(sep);
> > > >         if (stream == NULL)
> > > >                 goto fail;
> > > >
> > > > bluez-5.66 Works fine though.
> > > >
> > > > Headset: WH-1000XM3
> > > >
> > > >   Jocke
> > >
> > > Weird, I don't think much has changed for A2DP, but perhaps there is
> > > some BAP related changes affecting A2DP for some reason, any chance to
> > > bisect the patch that introduces this problem? Or it is not always
> > > reproducible?
> >
> > It is reproducible but on an remote laptop used for daily work so would disturb quite a lot.
> > Can I turn off BAP somehow to see if it is interfering ?
> >
> > Any chance it is related to https://github.com/bluez/bluez/issues/533 ?
>
> Right, yeah that is possible since it appears to be some unbalanced
> reference count issue, that said that was a very old version, not sure
> if we haven't fixed that.

It is not fixed in unref code discussed in that issue on master

    Jocke