Confused by segfault with legitimate call to strerror(3) on amd64 / sysctl (3) setting `odd' errno's

[Danny Braniss]

> Garrett Cooper schrieb:
> >     Ok, I just installworld'ed, recompiled the program with the
> > following modifications, and I still get segfaults. And the question
> > of the night is: why amd64 on a VERY recent CURRENT?
> >     I'm going to try the same app on an amd64 freebsd VMware instance
> > with RELENG_7.
> >     Remember: just because a bunch of other people aren't reporting
> > issues with CURRENT/amd64 doesn't mean that it isn't environmental,
> > related to my hardware or compile options ;).
> > Cheers,
> > -Garrett
> > 
> > #include <errno.h>
> > #include <stdio.h>
> > #include <sys/stat.h>
> > 
> > int
> > main()
> > {
> > 
> >         struct stat sb;
> > 
> >         int o_errno;
> > 
> >         if (stat("/some/file/that/doesn't/exist", &sb) != 0) {
> >                 o_errno = errno;
> >                 printf("Errno: %d\n", errno);
> >                 printf("%s\n", strerror(o_errno));
> >         }
> > 
> >         return 0;
> > 
> > }
> > 
> > #include <errno.h>
> > #include <stdio.h>
> > #include <sys/stat.h>
> > 
> > int
> > main()
> > {
> > 
> >         struct stat sb;
> > 
> >         int o_errno;
> > 
> >         if (stat("/some/file/that/doesn't/exist", &sb) != 0) {
> >                 o_errno = errno;
> >                 printf("Errno: %d\n", errno);
> >                 printf("%s\n", strerror(o_errno));
> >         }
> > 
> >         return 0;
> > 
> > }
> > 
> > [gcooper at optimus ~]$ gcc -o badfile badfile.c
> > [gcooper at optimus ~]$ ./badfile
> > Errno: 2
> > Segmentation fault: 11 (core dumped)
> > [gcooper at optimus ~]$
> 
> Well, compile with -g, start in gdb, check what value is wrong, the 
> usual stuff. Probably the return value of strerror() is interesting.

some facts:
#include <stdio.h>
int
main()
{
     printf("%s\n", strerror(2));
     return 0;
}

	1- it works fine on i386
	2- it bombs on amd64
	3- with a local strerror.c (instead of the one in libc)
	   works fine
so, there is something realy wrong going on here!
(and it gows back to at least 7.0-stable)

danny