On Thu, Mar 01, 2018 at 10:07:05PM +0200, Denys Fedoryshchenko wrote:
> On 2018-03-01 22:01, Guillaume Nault wrote:
> > diff --git a/drivers/net/ppp/ppp_generic.c
> > b/drivers/net/ppp/ppp_generic.c
> > index 255a5def56e9..2acf4b0eabd1 100644
> > --- a/drivers/net/ppp/ppp_generic.c
> > +++ b/drivers/net/ppp/ppp_generic.c
> > @@ -3161,6 +3161,15 @@ ppp_connect_channel(struct channel *pch, int
> > unit)
> > goto outl;
> >
> > ppp_lock(ppp);
> > + spin_lock_bh(&pch->downl);
> > + if (!pch->chan) {
> > + /* Don't connect unregistered channels */
> > + ppp_unlock(ppp);
> > + spin_unlock_bh(&pch->downl);
This is obviously wrong. It should have been
+ spin_unlock_bh(&pch->downl);
+ ppp_unlock(ppp);
Sorry, I shouldn't have hurried.
This is fixed in the official version.
> > + ret = -ENOTCONN;
> > + goto outl;
> > + }
> > + spin_unlock_bh(&pch->downl);
> > if (pch->file.hdrlen > ppp->file.hdrlen)
> > ppp->file.hdrlen = pch->file.hdrlen;
> > hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
> Ok, i will try to test that at night.
> Thanks a lot! For me also problem solved anyway by removing unit-cache, just
> i think it's nice to have bug fixed :)
>
I think this bug has been there forever, indeed it's good to have it fixed.
Thanks a lot for your help (and patience!).
FYI, if you see accel-ppp logs like
"ioctl(PPPIOCCONNECT): Transport endpoint is not connected", then that
means the patch prevented the scenario that was leading to the original
crash.
Out of curiosity, did unit-cache really bring performance improvements
on your workload?
