From: Jiri Pirko <jiri@resnulli.us>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
"David S. Miller" <davem@davemloft.net>,
Alexander Duyck <aduyck@mirantis.com>,
Tom Herbert <tom@herbertland.com>, Jiri Pirko <jiri@mellanox.com>,
Hadar Hen Zion <hadarh@mellanox.com>,
Gao Feng <fgao@48lvckh6395k16k5.yundunddos.com>,
Eric Garver <e@erig.me>, Amir Vadai <amir@vadai.me>,
Network Development <netdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] flow_dissector: avoid uninitialized variable access
Date: Sat, 22 Oct 2016 08:55:48 +0200 [thread overview]
Message-ID: <20161022065548.GA1625@nanopsycho.orion> (raw)
In-Reply-To: <CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com>
Sat, Oct 22, 2016 at 03:48:48AM CEST, torvalds@linux-foundation.org wrote:
>On Fri, Oct 21, 2016 at 9:31 AM, Jiri Pirko <jiri@resnulli.us> wrote:
>>
>> I don't see how vlan could be used uninitialized. But I understand that
>> this is impossible for gcc to track it. Please just use uninitialized_var()
>
>Actually, I think we should never use "uninitialized_var()" except
>possibly for arrays or structures that gcc can complain about.
>
>It's a horrible thing to use, in that it adds extra cruft to the
>source code, and then shuts up a compiler warning (even the _reliable_
>warnings from gcc).
>
>It's much better to just initialize the variable, and if gcc some day
>gets smarter and sees that it is unnecessary and always overwritten,
>so much the better. The cost of initializing a single word is
>basically zero.
On the other hand, I would agrue that initializing a var to "some" value
that is never used might confuse the reader. He would naturally try to
understand the reason for that exact value in initialization.
prev parent reply other threads:[~2016-10-22 6:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-21 15:55 [PATCH] flow_dissector: avoid uninitialized variable access Arnd Bergmann
2016-10-21 16:31 ` Jiri Pirko
2016-10-21 21:05 ` Arnd Bergmann
2016-10-21 22:16 ` Arnd Bergmann
2016-10-22 15:57 ` Eric Garver
2016-10-22 18:20 ` Tom Herbert
2016-10-22 20:30 ` [PATCH net-next] flow_dissector: fix vlan tag handling Arnd Bergmann
2016-10-24 8:17 ` Jiri Pirko
2016-10-24 16:00 ` Arnd Bergmann
2016-10-22 1:48 ` [PATCH] flow_dissector: avoid uninitialized variable access Linus Torvalds
2016-10-22 6:55 ` Jiri Pirko [this message]
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