From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH] powerpc/futex: fix warning: 'oldval' may be used uninitialized in this function
Date: Wed, 14 Aug 2019 09:25:52 +0000 (UTC) [thread overview]
Message-ID: <86b72f0c134367b214910b27b9a6dd3321af93bb.1565774657.git.christophe.leroy@c-s.fr> (raw)
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
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
next reply other threads:[~2019-08-14 9:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 9:25 Christophe Leroy [this message]
2019-08-16 12:35 ` [PATCH] powerpc/futex: fix warning: 'oldval' may be used uninitialized in this function Michael Ellerman
2019-08-22 13:09 ` Michael Ellerman
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