Re: tcsh hangs in sigsuspend

At Sat, 30 Jun 2007 08:04:48 -0700,
Steve Kargl wrote:
> 
> On Sat, Jun 30, 2007 at 04:41:42PM +0200, Michiel Boland wrote:
> > Hi. I can no longer do simple things like
> > 
> >  kill `cat pidfile`
> > 
> > in tcsh.
> > 
> > After some debugging I noticed that tcsh hangs in sigsuspend in line 512 
> > of sh.proc.c. So I guess it (tcsh) executed 'cat pidfile', and now waits 
> > for the process to terminate. But unless I'm not looking properly, there 
> > appears to be a race condition here. Tcsh blocks the SIGCHLD signal 
> > *after* it forks the child, not before. So the child could wel have exited 
> > between the call to fork and the call to sigprocmask. In that case, would 
> > not the sigsuspend hang forever?
> > 
> > Also, I noticed that gdb gets very confused if I try to debug tcsh with 
> > a backticked command like the one above. (I guess this is the same as 
> > bin/112408)
> > 
> 
> I suspect it is the same problem.  Unfortunately, the author of
> tcsh does not have a publicly available source tree, so one cannot
> determine if the problem is fixed.  It looks like you've managed
> to go beyond the limited debugging I did in bin/112408.  Hopefully,
> this gets addressed before 7.0 is released. 

But you can consult the bug tracking system at http://bugs.gw.com/

Hope this helps.
--
Rui Paulo