Re: allocate_string_data memory corruption

[Ken Raeburn <raeburn@gnu.org>]

On Jan 22, 2006, at 11:45, Stefan Monnier wrote:
>> if you look at x_catch_errors, you'll see that it allocates one  
>> lisp_cons
>> cell, one lisp_string and one lisp_misc.  Whether it's the cause  
>> of the
>> bugs we see, I don't know, but since it's run from the signal  
>> handler, it
>> can be executed at potentially any time.
>
> The patch below should remove this particular problem.

> @@ -7495,16 +7500,23 @@
>       Display *dpy;
>  {
>    int count = SPECPDL_INDEX ();
> +  struct x_error_message_stack *data = malloc (sizeof (*data));

It may just push the memory corruption from the Lisp object pool to  
the malloc pool, since malloc isn't safe for signal handlers either.   
Is it possible to pre-allocate this storage on a per-display basis,  
or might we have to deal with multiple error messages from one server  
without a chance to do processing outside of the signal handler?

Ken