On Mon, Sep 28, 2015 at 07:08:19AM +0000, ???? / KAWAI?HIDEHIRO wrote: > > >> kernel/kexec_core.c:899:3: note: in expansion of macro 'atomic_xchg' > > atomic_xchg(&panic_cpu, -1); > > ^ > > I changed to use atomic_xchg() instead of atomic_set() in V3 > because atomic_set() doesn't mean memory barrier. However, > I thought again and there is no need of barrier; there is no > problem if a competitor sees old value of panic_cpu or new one. > So, atomic_set() is sufficient and using it will remove this warning. > > I will resend the fixed version later. So if you rely on the memory barrier; you should have also put a comment on explaining the ordering requirements.
