Date: Tue, 15 Apr 2014 09:50:45 +0000 From: Juergen Hannken-Illjes <hann...@netbsd.org>
Fix a deadlock where one thread exits, enters fstrans_lwp_dtor() and wants fstrans_lock. This thread holds the proc_lock. This sounds fishy. lwp_exit does not hold proc_lock while calling lwp_finispecific, so there are no invariants covered by proc_lock that the lwp_specific destructors can rely on. I'm inclined to say that it is a bug for exit1 to hold proc_lock when it calls lwp_finispecific (and proc_finispecific). Can we just release it before and re-acquire it after calling lwp/proc_finispecific? Another thread holds fstrans_lock and runs pserialize_perform(). As the first thread holds the proc_lock, timeouts are blocked and the second thread blocks forever in kpause(). This also sounds fishy. How does T1's holding proc_lock cause T2 to block forever in kpause? I think I'm missing something in this analysis. kpause doesn't take proc_lock, does it?