From: Christophe Leroy christophe.leroy@c-s.fr
[ Upstream commit 38a0d0cdb46d3f91534e5b9839ec2d67be14c59d ]
We see warnings such as: 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 0 and GCC doesn't see that it will only use it when ret is 0.
Anyway, the non-zero 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 [mpe: reword change log slightly] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/86b72f0c134367b214910b27b9a6dd3321af93bb.156577465... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 3a6aa57b9d901..eea28ca679dbb 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;