Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] powerpc/futex: fix warning: 'oldval' may be used uninitialized in this function | Date | Fri, 16 Aug 2019 22:35:31 +1000 |
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Christophe Leroy <christophe.leroy@c-s.fr> writes: > CC kernel/futex.o > kernel/futex.c: In function 'do_futex': > kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] > return oldval == cmparg; > ^ > kernel/futex.c:1651:6: note: 'oldval' was declared here > int oldval, ret; > ^ > > This is because arch_futex_atomic_op_inuser() only sets *oval > if ret is NUL and GCC doesn't see that it will use it only when
I prefer 0 to "NUL", as ret is an int. I'll reword it. But otherwise this looks OK.
cheers
> ret is NUL. > > Anyway, the non-NUL ret path is an error path that won't suffer from > setting *oval, and as *oval is a local var in futex_atomic_op_inuser() > it will have no impact. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > --- > arch/powerpc/include/asm/futex.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h > index 3a6aa57b9d90..eea28ca679db 100644 > --- a/arch/powerpc/include/asm/futex.h > +++ b/arch/powerpc/include/asm/futex.h > @@ -60,8 +60,7 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, > > pagefault_enable(); > > - if (!ret) > - *oval = oldval; > + *oval = oldval; > > prevent_write_to_user(uaddr, sizeof(*uaddr)); > return ret; > -- > 2.13.3
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