Date: Mon, 30 Aug 2010 16:45:44 +0200
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: Uninitialized variable usage in cygthread?
Message-ID: <20100830144544.GO6726@calimero.vinschen.de>
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On Aug 30 10:26, Edward Lam wrote:
> Hi,
> 
> In looking at slowdown problem on x64 systems by Sagi Ben-Akiva, I
> found some puzzling code that perhaps someone could enlighten me on.
> I must be reading it wrong.
> 
> Here's the code path that I'm tracing using cygwin-src-20100829.tar.bz2:
> 
> - In dcrt0.cc, if dynamically_loaded is true, then we call sigproc_init().
> 
> - In sigproc.cc, sigproc_init() creates a new thread:
>   hwait_sig = new cygthread (wait_sig, 0, cygself, "sig");
> 
> - This calls the cygthread constructor for LPTHREAD_START_ROUTINE.
> (Actually, this doesn't really matter because the constructor for
> LPVOID_START_ROUTINE looks like it has the same problem.)
> 
> - The cygthread constructor calls create(). But prior to this, the
> following class members are initialized:
> __name, func, arglen, arg, notify_detached
> 
> - The following class members are NOT initialized (assuming that the
> macro DEBUGGING is NOT set):
> inuse, id, h, ev, thread_sync, stack_ptr, is_freerange
> 
> - Ok, now the cygthread constructor calls cygthread::create()
> 
> - In cygthread.cc, cygthread::create() immediately checks the value
> of the variable "h". But as mentioned previously, this is a variable
> that has not been initialized yet.
> 
> 
> What am I missing?

cygthread::operator new(size_t)


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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