Re: GDB cannot access memory after Emacs abort

Stephen Berman
2007-11-13T22:40:09Z

On Sun, 11 Nov 2007 21:15:55 -0800 Michael Snyder <msnyder@specifix.com> wrote:

> On Mon, 2007-11-12 at 00:01 +0100, Stephen Berman wrote:
>> On Sun, 11 Nov 2007 09:44:23 +0200 Eli Zaretskii <eliz@gnu.org> wrote:
>>
>> > the upshot of all this is that `bt' doesn't
>> > work, as shown below:
>> >
>> >> > > (gdb) bt
>> >> > > #0 abort () at emacs.c:431
>> >> > > Cannot access memory at address 0xbfd6836c
>> >> > > Cannot access memory at address 0x8321b6c
>> >
[...]
> I wonder -- after the above happens, what do you get if you
> type the following at the (gdb) prompt:
>
> x /i $eip

After the abort occurs, the desktop locks up, I switch to a virtual tty
and kill -9 the emacs process, releasing the desktop, then type what you
said at the gdb prompt and get this:

0x80f9e56 <abort+6>: Cannot access memory at address 0x80f9e56

In this case, bt returned this:

Cannot access memory at address 0xbf855e4c
Cannot access memory at address 0x8322c0c

> If you get the same error (Cannot access memory at ...),
> then perhaps gdb has lost contact with the child process
> entirely, and cannot access *any* memory.

Yes, this is also what Jim Blandy surmised. But, as I ask in my
response to Blandy, why does the desktop lock up only happen when the
emacs abort is induced while running under gdb?

Steve Berman