Re: VM crashes on big INBOX file

[Baoqiu.Cui@yahoo.com]

Baoqiu.Cui@yahoo.com writes:

> Reiner Steib <reinersteib+from-uce@imap.cc> writes:
>
>>>>I also tried splitting this big folder into two (one with 44MB and
>>>>one with 35MB), and VM can also crash on the small ones sometimes.
>>
>> Please clarify if *Emacs* or *VM* crashes.  (What to you mean by
>> "crash"?)
>
> It is Emacs that crashes...  Everything is gone except a line of
> "Segmentation fault    emacs" on the console.  I can easily recreate
> this using the 79MB folder.

OK.  After running GDB on Emacs, I finally found the real cause for the
crash.  The problem is that, when VM is visiting the huge 79MB folder,
garbage collection is triggered and function mark_object() (in alloc.c)
is recursively called about 29,885 times!!!  Too many levels of
mark_object() calls make the stack overflow, causing a segmentation
fault.

Since I am running Emacs on Cygwin, I had to change the following line
in src/Makefile

  LD=$(CC) -Wl,--image-base,0x20000000

to something like

  LD=$(CC) -Wl,--image-base,0x20000000,--stack,8000000

to increase the stack limit to ~8MB.  After making this change and
rebuilding Emacs, now I am able to read the huge folder without any
problem.

Maybe some comments could be added in etc/PROBLEMS for such a problem.
Apparently, XEmacs has a higher stack limit on Cygwin.

Thanks to all of your for the help!

- Baoqiu