On Wed, Nov 04 2020 at 08:42, Mike Galbraith wrote: > On Wed, 2020-11-04 at 01:56 +0100, Mike Galbraith wrote: > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2383,7 +2383,18 @@ static int fixup_pi_state_owner(u32 __us > * Since we just failed the trylock; there must be an owner. > */ > newowner = rt_mutex_owner(&pi_state->pi_mutex); > - BUG_ON(!newowner); > + > + /* > + * Why? Because I know what I'm doing with these beasts? Nope, > + * but what the hell, a busy restart loop let f_boosted become > + * owner, so go for it. Box still boots, works, no longer makes > + * boom with fbomb_v2, and as an added bonus, didn't even blow > + * futextests all up. Maybe it'll help... or not, we'll see. > + */ > + if (unlikely(!newowner)) { > + err = -EAGAIN; > + goto handle_err; Yes, that cures it, but does not really explain why newowner is NULL. Lemme stare more.