Re: [PATCH] futex: Handle transient "ownerless" rtmutex state correctly

[Thomas Gleixner]

On Wed, Nov 04 2020 at 16:12, Thomas Gleixner wrote:

> From: Mike Galbraith <efault@xxxxxx>
>
> Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner().
> This is one possible chain of events leading to this:
>
> Task Prio       Operation
> T1   120	lock(F)
> T2   120	lock(F)   -> blocks (top waiter)
> T3   50 (RT)	lock(F)   -> boosts T3 and blocks (new top waiter)

boosts T1 obviously as Sebastian just pointed out to me. /me pulls the
futex induced brain damage excuse ...