From c628123952112281ef12990ff69565fc059c40ba Mon Sep 17 00:00:00 2001 From: marcel Date: Wed, 28 May 2008 16:41:02 +0000 Subject: Work-around a compiler optimization bug, that broke libthr. Massive inlining resulted in constant propagation to the extend that cmpval was known to the compiler to be URWLOCK_WRITE_OWNER (= 0x80000000U). Unfortunately, instead of zero-extending the unsigned constant, it was sign-extended. As such, the cmpxchg instruction was comparing 0x0000000080000000LU to 0xffffffff80000000LU and obviously didn't perform the exchange. But, since the value returned by cmpxhg equalled cmpval (when zero- extended), the _thr_rtld_lock_release() function thought the exchange did happen and as such returned as if having released the lock. This was not the case. Subsequent locking requests found rw_state non-zero and the thread in question entered the kernel and block indefinitely. The work-around is to zero-extend by casting to uint64_t. --- sys/ia64/include/atomic.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'sys/ia64') diff --git a/sys/ia64/include/atomic.h b/sys/ia64/include/atomic.h index fd90fa2..631193f 100644 --- a/sys/ia64/include/atomic.h +++ b/sys/ia64/include/atomic.h @@ -42,7 +42,7 @@ "mov ar.ccv=%2;;\n\t" \ "cmpxchg" #sz "." #sem " %0=%4,%3,ar.ccv\n\t" \ : "=r" (ret), "=m" (*p) \ - : "r" (cmpval), "r" (newval), "m" (*p) \ + : "r" ((uint64_t)cmpval), "r" (newval), "m" (*p) \ : "memory") /* -- cgit v1.1