Re: Calls to malloc during an exception

["H. J. Lu" <hjl at lucon dot org>]

On Wed, Jan 18, 2006 at 11:41:39AM -0600, Perry Smith wrote:
> In the course of doing my work last week to get exception handling  
> working in my device driver, I learned that the exception processing  
> code calls malloc during the exception.  This seems weak to me.  It  
> seems like one of the most critical times to throw an exception is  
> when malloc fails.
> 
> I did not study the code very much to see what happens if the malloc  
> fails during the exception processing but I assume its not good.
> 
> It seems like a better approach would be to pre-allocate storage and  
> use it during the exception handling.  The design objective, to me,  
> would be to make the exception handling as bullet proof as possible.   
> I understand that it is not known how many exceptions are going to  
> stack up but I think taking a reasonable guess, pre-allocating that  
> space, and then fall back to malloc when that space fills up would be  
> much less likely to fail during a critical time.
> 
> Has this been considered?

It is a major flaw in the gcc exception handling. I'd like to see it
get fixed.


H.J.