tlibthread: abort on single-threaded lock contention - plan9port - [fork] Plan 9 from user space
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---
DIR commit faf1fb6c7e14e95e54865b660db7501ed390ea9e
DIR parent f35a04866f298aa4b0fa6846da0c0187751ce9b2
HTML Author: Russ Cox <rsc@swtch.com>
Date: Wed, 9 Jul 2008 11:41:14 -0400
libthread: abort on single-threaded lock contention
Diffstat:
M src/libthread/thread.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+), 0 deletions(-)
---
DIR diff --git a/src/libthread/thread.c b/src/libthread/thread.c
t@@ -463,6 +463,12 @@ needstack(int n)
}
}
+static int
+singlethreaded(void)
+{
+ return threadnproc == 1 && _threadprocs->nthread == 1;
+}
+
/*
* locking
*/
t@@ -481,6 +487,12 @@ threadqlock(QLock *l, int block, ulong pc)
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);
t@@ -537,6 +549,10 @@ threadrlock(RWLock *l, int block, ulong pc)
unlock(&l->l);
return 0;
}
+ if(singlethreaded()){
+ fprint(2, "rlock deadlock\n");
+ abort();
+ }
addthread(&l->rwaiting, (*threadnow)());
unlock(&l->l);
_threadswitch();
t@@ -558,6 +574,10 @@ threadwlock(RWLock *l, int block, ulong pc)
unlock(&l->l);
return 0;
}
+ if(singlethreaded()){
+ fprint(2, "wlock deadlock\n");
+ abort();
+ }
addthread(&l->wwaiting, (*threadnow)());
unlock(&l->l);
_threadswitch();
t@@ -613,6 +633,10 @@ threadwunlock(RWLock *l, ulong pc)
static void
threadrsleep(Rendez *r, ulong pc)
{
+ if(singlethreaded()){
+ fprint(2, "rsleep deadlock\n");
+ abort();
+ }
addthread(&r->waiting, proc()->thread);
qunlock(r->l);
_threadswitch();