On Sun, 2009-06-28 at 15:18 +0300, Ivan Kuten wrote:
> Hello,
>
> In net/wireless/scan.c : cfg80211_wext_siwscan there seems also unaligned allocations
> for creq->ssids and creq->channels. Should it be something like that?
Seems alright, but there is more than one instance of this, maybe you
can make a function to allocate a scan request properly and have it be
called from all the places it's needed.
johannes
> Modified: trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c
> ==============================================================================
> --- trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c (original)
> +++ trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c Fri Jun 26 14:00:52 2009
> @@ -619,7 +619,7 @@
> if (wiphy->bands[band])
> n_channels += wiphy->bands[band]->n_channels;
>
> - creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
> + creq = kzalloc(roundup(sizeof(*creq), 4) + roundup(sizeof(struct cfg80211_ssid), 4) +
> n_channels * sizeof(void *),
> GFP_ATOMIC);
> if (!creq) {
> @@ -629,8 +629,8 @@
>
> creq->wiphy = wiphy;
> creq->ifidx = dev->ifindex;
> - creq->ssids = (void *)(creq + 1);
> - creq->channels = (void *)(creq->ssids + 1);
> + creq->ssids = (void *)creq + roundup(sizeof(*creq), 4);
> + creq->channels = (void *)creq->ssids + roundup(sizeof(*creq->ssids), 4);
> creq->n_channels = n_channels;
> creq->n_ssids = 1;
>
> Regards,
> Ivan
>
> > 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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