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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH] net: compare_ether_addr[_64bits]() has no ordering
Date: Mon, 07 May 2012 15:53:29 +0200	[thread overview]
Message-ID: <1336398809.3752.2313.camel@edumazet-glaptop> (raw)
In-Reply-To: <1336397946.4325.27.camel@jlt3.sipsolutions.net>

On Mon, 2012-05-07 at 15:39 +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> Neither compare_ether_addr() nor compare_ether_addr_64bits()
> (as it can fall back to the former) have comparison semantics
> like memcmp() where the sign of the return value indicates sort
> order. We had a bug in the wireless code due to a blind memcmp
> replacement because of this.
> 
> A cursory look suggests that the wireless bug was the only one
> due to this semantic difference.
> 
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
>  include/linux/etherdevice.h |   11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)

The right way to avoid this kind of problems is to change these
functions to return a bool

  reply	other threads:[~2012-05-07 13:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-07 13:39 [PATCH] net: compare_ether_addr[_64bits]() has no ordering Johannes Berg
2012-05-07 13:53 ` Eric Dumazet [this message]
2012-05-07 14:12   ` Johannes Berg
2012-05-07 23:20     ` David Miller
2012-05-08  5:25       ` Johannes Berg
2012-05-08  6:26         ` David Miller
2012-05-08  6:35           ` Joe Perches
2012-05-08  7:31             ` David Miller
2012-05-08 16:44               ` Joe Perches
2012-05-08 16:44               ` [PATCH] etherdev.h: Convert int is_<foo>_ether_addr to bool Joe Perches
2012-05-08 17:07                 ` David Miller

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