Add a simple work-around for deadlocking on recursive read locks

on a rwlock while there are writers waiting.  We normally favor
writers but when a reader already has at least one other read lock,
we favor the reader.  We don't track all the rwlocks owned by a
thread, nor all the threads that own a rwlock -- we just keep
a count of all the read locks owned by a thread.

PR:	24641

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/libpthread/thread/thr_create.c b/lib/libpthread/thread/thr_create.c
index b82f1809..38c2fc4 100644
--- a/lib/libpthread/thread/thr_create.c
+++ b/lib/libpthread/thread/thr_create.c
@@ -252,6 +252,7 @@ _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
 			sigemptyset(&new_thread->sigpend);
 			new_thread->check_pending = 0;
 			new_thread->locklevel = 0;
+			new_thread->rdlock_count = 0;
 			new_thread->sigstk.ss_sp = 0;
 			new_thread->sigstk.ss_size = 0;
 			new_thread->sigstk.ss_flags = SS_DISABLE;