printf crashes?

[Leon Pollak]

Hello, all.

For the third day I am fighting with the problem: my rtems 4.8.0, MPC8260 
application performs "brunch to zero address" (break point is set on address 
zero) from inside the:
../newlib/libc/stdio/fflush.c:196 (_fflush_r routine)
../newlib/libc/stdio/fvwrite.c:257 (__sfvwrite_r routine)
../newlib/libc/stdio/vfprintf.c:177 (__sprint_r routine)
../newlib/libc/stdio/vfprintf.c:1329 (_vfprintf_r routine)
../newlib/libc/stdio/printf.c:52 (printf routine)
and the calling printf is:
printf("W=%d P=%d\n", 1, 1);

The question is: as I do printf from several tasks (may be simultaneously), 
may this be the cause of the problem somehow?

I know that newlib is re-entrant, if some precautions are taken. But are they 
taken by default, or I need to do something special (never previously used 
printf extensively)?

Many thanks ahead for any advice.
-- 
Leon