libpager: fix potential deadlock

This patch releases the interlock before doing an rpc call, analogous
to 901c61a1d25e7c8963e51012760a82730eda1910.

* libpager/pager-attr.c (pager_change_attributes): Release interlock
before calling memory_object_change_attributes, to let the callbacks
take it.

1 files changed, 5 insertions, 2 deletions

diff --git a/libpager/pager-attr.c b/libpager/pager-attr.c
index 47da12ac..ad1560ea 100644
--- a/libpager/pager-attr.c
+++ b/libpager/pager-attr.c
@@ -77,11 +77,14 @@ pager_change_attributes (struct pager *p,
 	}
     }      
 
+  pthread_mutex_unlock (&p->interlock);
   memory_object_change_attributes (p->memobjcntl, may_cache, copy_strategy,
 				   wait ? p->port.port_right : MACH_PORT_NULL);
   
   if (wait)
     {
+      pthread_mutex_lock (&p->interlock);
+
       while (ar->attrs_pending)
 	pthread_cond_wait (&p->wakeup, &p->interlock);
 
@@ -92,7 +95,7 @@ pager_change_attributes (struct pager *p,
 	    ar->next->prevp = ar->prevp;
 	  free (ar);
 	}
+
+      pthread_mutex_unlock (&p->interlock);
     }
-  
-  pthread_mutex_unlock (&p->interlock);
 }