From: Johannes Berg <johannes@sipsolutions.net>
To: Yauhen Kharuzhy <yauhen.kharuzhy@promwad.com>
Cc: linux-wireless@vger.kernel.org
Subject: Re: [PATCH] wireless: Compare ethernet addresses by unaligned safe way
Date: Tue, 16 Jun 2009 13:14:55 +0200 [thread overview]
Message-ID: <1245150895.8623.3.camel@johannes.local> (raw)
In-Reply-To: <1245149672-18063-1-git-send-email-yauhen.kharuzhy@promwad.com>
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On Tue, 2009-06-16 at 13:54 +0300, Yauhen Kharuzhy wrote:
> When we try to run RTL8187 driver on AD BlackFin platform, we got
> messages from kernel about unaligned memory access at
> compare_ether_addr() calls.
>
> Replacing of compare_ether_addr() by memcmp() fixes this problem.
This shouldn't be necessary. Which operand is unaligned?
> --- a/net/mac80211/ibss.c
> +++ b/net/mac80211/ibss.c
> @@ -395,7 +395,7 @@ struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
> return NULL;
> }
>
> - if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
> + if (memcmp(bssid, sdata->u.ibss.bssid, ETH_ALEN))
> return NULL;
So in this case it seems that it is possible that u.ibss.bssid is not
aligned, consider fixing by doing
--- ieee80211_i.h
+++ ieee80211_i.h
- u8 bssid[ETH_ALEN];
+ u8 bssid[ETH_ALEN] __align(2);
or so instead.
> --- a/net/wireless/scan.c
> +++ b/net/wireless/scan.c
> @@ -134,7 +134,7 @@ static bool is_bss(struct cfg80211_bss *a,
> {
> const u8 *ssidie;
>
> - if (bssid && compare_ether_addr(a->bssid, bssid))
> + if (bssid && memcmp(a->bssid, bssid, ETH_ALEN))
Since a->bssid is after a pointer I can't see how it would be unaligned,
and bssid should be unaligned only if the call trace shows it's coming
from the above u.ibss.bssid.
johannes
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next prev parent reply other threads:[~2009-06-16 11:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 10:54 [PATCH] wireless: Compare ethernet addresses by unaligned safe way Yauhen Kharuzhy
2009-06-16 11:14 ` Johannes Berg [this message]
2009-06-28 12:18 ` Ivan Kuten
2009-06-29 7:58 ` Johannes Berg
2009-07-23 17:56 ` Ivan Kuten
2009-07-23 17:59 ` Johannes Berg
2009-08-07 15:34 ` John W. Linville
2009-06-29 8:23 ` Johannes Berg
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