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: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.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
WARNING: multiple messages have this Message-ID (diff)
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 9:25 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-14 9:25 Christophe Leroy [this message] 2019-08-14 9:25 ` [PATCH] powerpc/futex: fix warning: 'oldval' may be used uninitialized in this function Christophe Leroy 2019-08-16 12:35 ` Michael Ellerman 2019-08-16 12:35 ` Michael Ellerman 2019-08-22 13:09 ` Michael Ellerman
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