building up glibc with --enable-profile and then trying to use the resulting
library like so:
$ cat test.c
main(){}
$ gcc test.c -static -pg -lc_p -g

results in a crash:
$ gdb ./a.out
(gdb) r
Starting program: /home/vapier/test

Program received signal SIGSEGV, Segmentation fault.
0x000000000042fecb in __mcount_internal ()
(gdb) bt
#0  0x000000000042fecb in __mcount_internal ()
#1  0x000000000040dc04 in mcount ()
#2  0x0000000000000000 in ?? ()
(gdb)

the crash seems to be because gmon/mcount.c uses atomic code which relies on the
TLS descriptors being setup, but that doesnt happen until __libc_start_main.  but
since __libc_start_main itself (and other functions early on) calls mcount, we
crash.

crash is easily reproducible with current git and x86_64 or x86.  it's been this
way since at least glibc-2.6.1.