Mailing-List: contact cygwin-help@sourceware.cygnus.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@sources.redhat.com Delivered-To: mailing list cygwin@sources.redhat.com Date: Thu, 30 Aug 2001 09:46:00 +0200 From: Frederic Devernay To: cygwin@cygwin.com Cc: Olivier Bantiche , Frederic Devernay Subject: possible pthread_mutex_init bug: reads uninitialized memory Message-ID: <20010830094600.A9594@perf.inria.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.4i Hello, there are officially two ways to initialize a pthread mutex: pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER; or pthread_mutex_t mut; pthread_mutex_init(&mut,NULL); the problem is that the pthread_mutex_init in cygwin reads the of-course uninitialized memory: as seen in cygwin-1.3.2-1/winsup/cygwin/thread.cc: __pthread_mutex_init (pthread_mutex_t * mutex, const pthread_mutexattr_t * attr) { if ((((pshared_mutex *)(mutex))->flags & SYS_BASE == SYS_BASE)) // a pshared mutex return EBUSY; ... If found this bug not by declaring a local variable as above, but by allocating the mutex. the only workaround I found was to memset the memory area before calling pthread_mutex_init. I don't know what a pshared_mutex is, but pthread_mutex_init should really not assume that anything is valid in the given mutex! Fred -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/