Re: redboot fconfig crash with gcc 4.3.2

[Gary Thomas <gary@mlbassoc.com>]

Jose Vasconcellos wrote:
> Redboot gets an exception when trying to set any IP address with fconfig
> when using gcc-4.3.2 on an ixp425 target (armeb). The issue seems to be
> an alignment problem as val_ptr contains an odd address; it looks like gcc
> is optimizing and trying to do a copy on a word boundary. The removal of
> the cast fixes the problem.
> 
> 
> --- fconfig.c    2009-01-18 14:34:11.000000000 -0500
> +++ fconfig.c.new    2009-01-18 14:35:22.000000000 -0500
> @@ -388,7 +388,7 @@
>        break;
> #ifdef CYGPKG_REDBOOT_NETWORKING
>    case CONFIG_IP:
> -        memcpy(&hold_ip_val.s_addr, &((in_addr_t *)val_ptr)->s_addr, 
> sizeof(in_addr_t));
> +        memcpy(&hold_ip_val.s_addr, val_ptr, sizeof(in_addr_t));
>        if (!_gethostbyname(line, &new_ip_val)) {
>            return CONFIG_BAD;
>        }
> 

Sounds like a *BUG* in the compiler.  Have you reported it?

This does more than remove the cast :-)  What if the s_addr field is not
at the start of the structure?  I know it hasn't moved in 25+ years, but
I don't like tossing correctness [even if only pedantic] away.

Maybe there's another way to solve this.  Does it happen on arm[el]?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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