On Sat, Jun 10, 2017 at 04:02:12PM +0200, Peter Zijlstra wrote: > On Sat, Jun 10, 2017 at 02:48:04AM +0000, Levin, Alexander (Sasha Levin) > wrote: > > lockdep can't deal with NULL name or key, and doesn't do anything > > with the lock when that happens. > > Not doing anything is 'right', the proxy stuff won't be lockdep tracked > anyway. But yeah, the first thing is a wee bit of a problem, for it will > trigger DEBUG_LOCKS_WARN_ON() and fully kill lockdep.
But don't we want pi_state->pi_mutex tracked by lockdep? > Yeah, no need to do that; all we really need here is something like: > > --- > kernel/locking/rtmutex-debug.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c > index ac35e648b0e5..8dc647dc4b4b 100644 > --- a/kernel/locking/rtmutex-debug.c > +++ b/kernel/locking/rtmutex-debug.c > @@ -175,7 +175,8 @@ void debug_rt_mutex_init(struct rt_mutex *lock, const > char *name, struct lock_cl > lock->name = name; > > #ifdef CONFIG_DEBUG_LOCK_ALLOC > - lockdep_init_map(&lock->dep_map, name, key, 0); > + if (name && key) > + lockdep_init_map(&lock->dep_map, name, key, 0); > #endif > } I didn't want to do that because in later calls on that mutex we will end up going into lockdep code, and I didn't think that doing that without calling lockdep_init_map() initially was safe. -- Thanks, Sasha
