From: Vlad Yasevich <vyasevich@gmail.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, linux-sctp@vger.kernel.org
Subject: Re: [PATCH] sctp: Clean up type-punning in sctp_cmd_t union
Date: Fri, 26 Oct 2012 22:16:39 -0400 [thread overview]
Message-ID: <508B4407.7070300@gmail.com> (raw)
In-Reply-To: <20121027014249.GA4008@neilslaptop.think-freely.org>
On 10/26/2012 09:42 PM, Neil Horman wrote:
> On Fri, Oct 26, 2012 at 05:10:19PM -0400, David Miller wrote:
>> From: Neil Horman <nhorman@tuxdriver.com>
>> Date: Fri, 26 Oct 2012 16:35:04 -0400
>>
>>> On Fri, Oct 26, 2012 at 03:12:11PM -0400, Vlad Yasevich wrote:
>>>> Look at commit 19c7e9ee that introduced this. I don't remember all
>>>> the details any more, but the problem only occurred on ia64
>>>> (probably due its speculative load handling).
>>>>
>>>> -vlad
>>>>
>>> Thanks Vlad, I'll have a look see.
>>
>> Ok, so this IA64 issue is all about accesses to uninitialized memory.
>>
>> I think Neil's change is thus the most desirable thing to do. Simple
>> memset the object to zero.
>>
>> Let the compiler optimize or not optimize things as it sees fit, to
>> make sure the object is completely initialized.
>>
>> memset() expands to __builtin_memset(), and therefore the compiler
>> can and will eliminate initializations to overlapping areas if such
>> eliminations are possible.
>>
> If thats the case, then I'll need to duplicate the memset in all three call
> sites. I've got a busy weekend comming up, but I'll respin this monday barring
> no objections or counter-arguments
>
> Best
> Neil
>
Yes, it should be done in all 3 call sights. If you are going with
memset, you can remove .zero element as well.
-vlad
next prev parent reply other threads:[~2012-10-27 2:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 20:47 [PATCH] sctp: Clean up type-punning in sctp_cmd_t union Neil Horman
2012-10-25 21:42 ` Vlad Yasevich
2012-10-25 23:58 ` Neil Horman
2012-10-26 3:48 ` Vlad Yasevich
2012-10-26 13:24 ` Neil Horman
2012-10-26 19:12 ` Vlad Yasevich
2012-10-26 20:35 ` Neil Horman
2012-10-26 21:10 ` David Miller
2012-10-27 1:42 ` Neil Horman
2012-10-27 2:16 ` Vlad Yasevich [this message]
2012-10-29 15:07 ` David Laight
2012-10-29 18:59 ` Neil Horman
2012-10-29 19:04 ` David Miller
2012-10-26 9:00 ` David Laight
2012-10-26 13:28 ` Neil Horman
2012-10-26 13:41 ` [PATCH v2] " Neil Horman
2012-10-26 19:12 ` Vlad Yasevich
2012-10-29 16:35 ` Neil Horman
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