Christopher Faylor <cgf-use-the-mailinglist-ple...@cygwin.com> writes:
> On Tue, Jul 28, 2009 at 10:52:44AM +0800, Haojun Bao wrote: >>I have debugged it again, and I think I have more clue. I have read the >>how-cygheap-works.txt, and this might be a known problem. >> >>It's because the cygheap space has been used up. With Procexp, I can see >>cygwin1.dll is based 0x61000000, with size 0x300000 (3M). When segfault >>is about to happen, cygheap_max is 0x6164e924, and the _csbrk is called >>with a increase of >> (gdb) p sbs >> $16 = 65544 >>This will increase cyghead to 0x6165e92c, but from Proxexp I can see >>cygncurses-9.dll is based at 0x61650000. >> >>Besides, this code snippet from pipe.cc fhandler_pipe::create didn't >>check for NULL pointer, and directly caused the segfault. >> >> fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev); >> fhs[1] = (fhandler_pipe *) build_fh_dev (*pipew_dev); >> >>//bhj: we should check NULL here. > > Not necessarily. We don't expect these functions to return NULL. It > would be interesting to know how many fds are open at this point. If it > is a large number then maybe we have to start enforcing an fd max. If > it is a "small" number then something is wrong and we're allocating too > much of the cygheap. The cygheap was always supposed to be relatively > small. Maybe we're abusing it too much in 1.7. There are quite some fds. In start-process, emacs will allocate 1 PTY and 1 pipe for each process it starts. Each fhandler_base is about 32K, but the _csbrk must allocate 65544 bytes for it. -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
