Re: linux-next test error: WARNING: suspicious RCU usage in ipmr_device_event

From: Dmitry Vyukov
Date: Thu Apr 23 2020 - 04:49:53 EST


On Tue, Apr 21, 2020 at 1:21 PM Qian Cai <cai@xxxxxx> wrote:
> > On Apr 21, 2020, at 6:51 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> >
> > +linux-next, Stephen for a new linux-next breakage
>
> I donât know why you keep sending the same thing over and over again where I replied you just two days ago for the same thing.

Well, formally this bug was never mailed. The other one is about
"WARNING: suspicious RCU usage in ovs_ct_exit". It just happened that
this "WARNING: suspicious RCU usage in ipmr_device_event" was appended
to that one (because kernel somehow failed to respect panic_on_warn?).
But warnings except the first one are ignored, frequently they are
induced and it's not possible to track 2 different bugs at the same
time in a reasonable way anyway.

So effectively this is the first occurance of this bug (presumably the
fix for ovs_ct_exit has reached linux-next). First occurrence is
always mailed.

Now let's tell syzbot that this one is fixed as well:

#syz fix: ipmr: Fix RCU list debugging warning