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libthread: abort on single-threaded lock contention

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This commit is contained in:
Russ Cox 2008-07-09 11:41:14 -04:00
parent f35a04866f
commit faf1fb6c7e
1 changed files with 24 additions and 0 deletions
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24
src/libthread/thread.c
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@ -463,6 +463,12 @@ needstack(int n)
} }
} }
static int
singlethreaded(void)
{
return threadnproc == 1 && _threadprocs->nthread == 1;
}
/* /*
* locking * locking
*/ */
@ -481,6 +487,12 @@ threadqlock(QLock *l, int block, ulong pc)
unlock(&l->l); unlock(&l->l);
return 0; return 0;
} }
if(singlethreaded()){
fprint(2, "qlock deadlock\n");
abort();
}
/*print("qsleep %p @%#x by %p\n", l, pc, (*threadnow)()); */ /*print("qsleep %p @%#x by %p\n", l, pc, (*threadnow)()); */
addthread(&l->waiting, (*threadnow)()); addthread(&l->waiting, (*threadnow)());
unlock(&l->l); unlock(&l->l);
@ -537,6 +549,10 @@ threadrlock(RWLock *l, int block, ulong pc)
unlock(&l->l); unlock(&l->l);
return 0; return 0;
} }
if(singlethreaded()){
fprint(2, "rlock deadlock\n");
abort();
}
addthread(&l->rwaiting, (*threadnow)()); addthread(&l->rwaiting, (*threadnow)());
unlock(&l->l); unlock(&l->l);
_threadswitch(); _threadswitch();
@ -558,6 +574,10 @@ threadwlock(RWLock *l, int block, ulong pc)
unlock(&l->l); unlock(&l->l);
return 0; return 0;
} }
if(singlethreaded()){
fprint(2, "wlock deadlock\n");
abort();
}
addthread(&l->wwaiting, (*threadnow)()); addthread(&l->wwaiting, (*threadnow)());
unlock(&l->l); unlock(&l->l);
_threadswitch(); _threadswitch();
@ -613,6 +633,10 @@ threadwunlock(RWLock *l, ulong pc)
static void static void
threadrsleep(Rendez *r, ulong pc) threadrsleep(Rendez *r, ulong pc)
{ {
if(singlethreaded()){
fprint(2, "rsleep deadlock\n");
abort();
}
addthread(&r->waiting, proc()->thread); addthread(&r->waiting, proc()->thread);
qunlock(r->l); qunlock(r->l);
_threadswitch(); _threadswitch();