>    Currently no one knows the right method to have such barrier,
   >    since __asm("":::"memory") no longer prevent it on gcc4.
   >    Do you have any idea?
   > 
   > does -O0 work?
   
   Even -O1 works, but I doubt it's worth only for a debug symbol.


perhaps a particular "-fbar-foo" is responsible for causing this to
happen?  i don't mind the kern_synch.c symbol going away, but the
ras test one seems to be useful more generally.  i wonder if it
is -funit-at-a-time... please try with -O2 -fno-unit-at-a-time.


thanks.