http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59644
--- Comment #8 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- >From the printk.i: 38333 int printk_emit(int facility, int level, 38334 const char *dict, size_t dictlen, 38335 const char *fmt, ...) 38336 { 38337 va_list args; 38338 int r; 38339 38340 __builtin_va_start(args,fmt); 38341 r = vprintk_emit(facility, level, dict, dictlen, fmt, args); 38342 __builtin_va_end(args); 38343 38344 return r; 38345 } 38346 ; 38347 # 1676 "kernel/printk/printk.c" 38348 int printk(const char *fmt, ...) 38349 { 38350 va_list args; 38351 int r; 38352 # 1689 "kernel/printk/printk.c" 38353 __builtin_va_start(args,fmt); 38354 r = vprintk_emit(0, -1, ((void *)0), 0, fmt, args); 38355 __builtin_va_end(args); 38356 38357 return r; 38358 } 38359 ; dump_stack_set_arch_desc is also a call wrapped by __builtin_va_start __builtin_va_end.