Problems related to Kaffe lockObjec/unlockObject

Zhu Wenzhang wzzhu at
Tue Nov 20 00:10:10 PST 2001

Dear all,
	In kaffe 1.0.6, the lockObject/unlockObject in locks.c are just a wrapper
of lockMutex/unlockMutex. In kaffe, lockObject uses "&obj" as the "where"
parameter in lockMutex. As the lockMutex and unlockMutex support recursive
locks, and determine whether it is a last unlock by the following checking :
	 if (lk->holder > where) {
	        putHeavyLock(lkp, lk);
	So the value of "where" is important for the unlocking.
	Now comes the problem.	When we call LockObject(obj) in one stack frame, the
slot address for obj(i.e. &obj)  is the address in the current frame. But
that slot address may be smaller than the stack address of object in a
subsequence call to unlockObj(obj); therefore that unlockObject(obj) will
mistakenly  assume that that is a recursive lock and won't unlock the
	Any comments will be appreciated. Thanks.

	Zhu Wenzhang

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