linux-kernel - Re: [PATCH] usercopy: Add parentheses around assignment in test_copy_struct_from

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Message-ID: <20191003173352.ai4wbllwo6lrxjju@yavin.dot.cyphar.com>
Date:   Fri, 4 Oct 2019 03:33:52 +1000
From:   Aleksa Sarai <cyphar@...har.com>
To:     Christian Brauner <christian@...uner.io>
Cc:     Nathan Chancellor <natechancellor@...il.com>,
        Kees Cook <keescook@...omium.org>,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com
Subject: Re: [PATCH] usercopy: Add parentheses around assignment in
 test_copy_struct_from_user

On 2019-10-03, Christian Brauner <christian@...uner.io> wrote:
> On Thu, Oct 3, 2019, 19:11 Nathan Chancellor <natechancellor@...il.com>
> wrote:
> 
> > Clang warns:
> >
> > lib/test_user_copy.c:96:10: warning: using the result of an assignment
> > as a condition without parentheses [-Wparentheses]
> >         if (ret |= test(umem_src == NULL, "kmalloc failed"))
> >             ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > lib/test_user_copy.c:96:10: note: place parentheses around the
> > assignment to silence this warning
> >         if (ret |= test(umem_src == NULL, "kmalloc failed"))
> >                 ^
> >             (                                              )
> > lib/test_user_copy.c:96:10: note: use '!=' to turn this compound
> > assignment into an inequality comparison
> >         if (ret |= test(umem_src == NULL, "kmalloc failed"))
> >                 ^~
> >                 !=
> >
> > Add the parentheses as it suggests because this is intentional.
> >
> > Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/731
> > Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> >
> 
> I'll take this. Aleksa, can I get your ack too, please?
> 
> Acked-by: Christian Brauner <christian.brauner@...ntu.com>

Acked-by: Aleksa Sarai <cyphar@...har.com>


-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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