From: Christophe Leroy <christophe.leroy@xxxxxx>
[ 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@xxxxxx>
[mpe: reword change log slightly]
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/86b72f0c134367b214910b27b9a6dd3321af93bb.1565774657.git.christophe.leroy@xxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
--
2.20.1
