On Mon, May 30, 2016 at 09:43:53AM +0200, Maarten Lankhorst wrote: > Op 26-05-16 om 22:08 schreef Chris Wilson: > > Recursive locking for ww_mutexes was originally conceived as an > > exception. However, it is heavily used by the DRM atomic modesetting > > code. Currently, the recursive deadlock is checked after we have queued > > up for a busy-spin and as we never release the lock, we spin until > > kicked, whereupon the deadlock is discovered and reported. > > > > A simple solution for the now common problem is to move the recursive > > deadlock discovery to the first action when taking the ww_mutex. > > > > Testcase: igt/kms_cursor_legacy
I've no idea what this tag is or where to find the actual testcase, so I've killed it. > > Suggested-by: Maarten Lankhorst <[email protected]> > > Signed-off-by: Chris Wilson <[email protected]> > > Cc: Peter Zijlstra <[email protected]> > > Cc: Ingo Molnar <[email protected]> > > Cc: Christian König <[email protected]> > > Cc: Maarten Lankhorst <[email protected]> > > Cc: [email protected] > > --- > > > > Maarten suggested this as a simpler fix to the immediate problem. Imo, > > we still want to perform deadlock detection within the spin in order to > > catch more complicated deadlocks without osq_lock() forcing fairness! > Reviewed-by: Maarten Lankhorst <[email protected]> > > Should this be Cc: [email protected] ? Can do; how far back?
