libthread: abort on single-threaded lock contention
diff --git a/src/libthread/thread.c b/src/libthread/thread.c
index 4e3e473..78c538a 100644
--- a/src/libthread/thread.c
+++ b/src/libthread/thread.c
@@ -463,6 +463,12 @@
}
}
+static int
+singlethreaded(void)
+{
+ return threadnproc == 1 && _threadprocs->nthread == 1;
+}
+
/*
* locking
*/
@@ -481,6 +487,12 @@
unlock(&l->l);
return 0;
}
+
+ if(singlethreaded()){
+ fprint(2, "qlock deadlock\n");
+ abort();
+ }
+
/*print("qsleep %p @%#x by %p\n", l, pc, (*threadnow)()); */
addthread(&l->waiting, (*threadnow)());
unlock(&l->l);
@@ -537,6 +549,10 @@
unlock(&l->l);
return 0;
}
+ if(singlethreaded()){
+ fprint(2, "rlock deadlock\n");
+ abort();
+ }
addthread(&l->rwaiting, (*threadnow)());
unlock(&l->l);
_threadswitch();
@@ -558,6 +574,10 @@
unlock(&l->l);
return 0;
}
+ if(singlethreaded()){
+ fprint(2, "wlock deadlock\n");
+ abort();
+ }
addthread(&l->wwaiting, (*threadnow)());
unlock(&l->l);
_threadswitch();
@@ -613,6 +633,10 @@
static void
threadrsleep(Rendez *r, ulong pc)
{
+ if(singlethreaded()){
+ fprint(2, "rsleep deadlock\n");
+ abort();
+ }
addthread(&r->waiting, proc()->thread);
qunlock(r->l);
_threadswitch();
