threads/81258: Thread specific data is sometimes assigned to
multiple keys and/or threads
Jens A Nilsson
jnilsson at ludd.ltu.se
Thu May 19 23:40:08 PDT 2005
The following reply was made to PR threads/81258; it has been noted by GNATS.
From: Jens A Nilsson <jnilsson at ludd.ltu.se>
To: Daniel Eischen <deischen at freebsd.org>
Cc: Jens Nilsson <jnilsson at ludd.luth.se>,
freebsd-gnats-submit at freebsd.org, freebsd-threads at freebsd.org
Subject: Re: threads/81258: Thread specific data is sometimes assigned to multiple keys and/or threads
Date: Fri, 20 May 2005 06:10:51 +0200
On Thu, May 19, 2005 at 08:52:23AM -0400, Daniel Eischen wrote:
> On Thu, 19 May 2005, Jens Nilsson wrote:
> > Thread specific data is sometimes assinged to multiple keys
> > and/or threads. In the attached test program two threads getting
> > the same tsd for the same key seems to be the most usual.
> > >How-To-Repeat:
> > Run the attached test program a couple of times. One of the
> > threads will wait for input, the bug is most likely to show up if
> > enter is pressed in about half a second after the thread asked
> > for data.
> > I ran into the bug some time ago while developing a bit more
> > complex application that involved a couple of threads all of them
> > with TSD and some doing RPC-calls. In that application I had the
> > same problem with any of the thread libs libpthread, libthr, and
> > libc_r. This test program only seems to be able to repeat the
> > problem with libpthread.
> Thread-specific data is destroyed when the thread exits. Your
> TSD is allocated using malloc() and destroyed using free(). Your
> test program does nothing to ensure that all threads have started
> running and have all created/initialized their TSD before the
> first thread exits. malloc() is probably reusing a prior
> allocation that has been free()'d.
> Thread exiting != Thread being joined.
I see, sorry to have bothered you.
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