Re: [PATCH] Fix computation of symbol size on corner case

[John L. <le...@mo...>]

On Thu, Jun 18, 2009 at 04:05:28PM -0500, Maynard Johnson wrote:

> A user just reported the following error to me:
>     opreport error: profile_t::samples_range(): start > end something wrong
>     with kernel or module layout ?
>     please report problem to opr...@li...
> 
> I discovered a bug in op_bfd:symbol_size() that was causing this.  I found that the symbol was apparently in the last section, so the code fell through to the "else" clause, so end was being set to "file_size".  In the case at hand, the sym filepos value (i.e., "start") was 0x19ee8 and file_size was 0x14bca; thus, start > end.  This particular piece of code exists for the corner case of last symbol in the last section.  Using 'file_size' as the default was, I presume, just a SWAG anyway.  The attached patch just ensures that SWAG will always provide an answer that is logically correct.

Why is a symbol claiming its position in the file is beyond the size of
the file?

regards
john