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From: Greg KH on 19 Mar 2010 00:10
On Fri, Mar 19, 2010 at 03:16:22AM +0100, Stefan Lippers-Hollmann wrote:
> Hi
>
> On Friday 19 March 2010, gregkh(a)suse.de wrote:
> > This is a note to let you know that we have just queued up the patch titled
> >
> > Subject: b43: Workaround circular locking in hw-tkip key update callback
> >
> > to the 2.6.33-stable tree. Its filename is
> [...]
> > From: Larry Finger <Larry.Finger(a)lwfinger.net>
> > Date: Wed, 10 Mar 2010 22:10:32 -0600
> > Subject: b43: Workaround circular locking in hw-tkip key update callback
> > To: Greg Kroah-Hartman <gregkh(a)suse.de>
> > Cc: Michael Buesch <mb(a)bu3sch.de>
> > Message-ID: <4b986d38.aOKVIPS3U9/aYsOP%Larry.Finger(a)lwfinger.net>
> >
> > From: Michael Buesch <mb(a)bu3sch.de>
> >
> > commit 96869a39399269a776a94812e9fff3d38b47d838 upstream
> >
> > The TKIP key update callback is called from the RX path, where the driver
> > mutex is already locked. This results in a circular locking bug.
> > Avoid this by removing the lock.
> >
> > Johannes noted that there is a separate bug: The callback still breaks on SDIO
> > hardware, because SDIO hardware access needs to sleep, but we are not allowed
> > to sleep in the callback due to mac80211's RCU locking.
> [...]
>
> This patch breaks compiling 2.6.33.1 + the current stable queue (and likely
> queue-2.6.32 as well):
>
> CC [M] drivers/net/wireless/b43/main.o
> drivers/net/wireless/b43/main.c: In function 'b43_op_update_tkip_key':
> drivers/net/wireless/b43/main.c:868: error: 'sta' undeclared (first use in this function)
> drivers/net/wireless/b43/main.c:868: error: (Each undeclared identifier is reported only once
> drivers/net/wireless/b43/main.c:868: error: for each function it appears in.)
>
> as it is based on the mac80211 API change of
>
> Gitweb: http://git.kernel.org/linus/b3fbdcf49f940d0703c356441e0daf045e64e076
> Commit: b3fbdcf49f940d0703c356441e0daf045e64e076
> Parent: e4fca007b06165900d0e44e8d5e251376819bf5d
> Author: Johannes Berg <johannes(a)sipsolutions.net>
> AuthorDate: Thu Jan 21 11:40:47 2010 +0100
> Committer: John W. Linville <linville(a)tuxdriver.com>
> CommitDate: Fri Jan 22 16:08:55 2010 -0500
>
> mac80211: pass vif and station to update_tkip_key
>
> When a TKIP key is updated, we should pass the station
> pointer instead of just the address, since drivers can
> use that to store their own data. We also need to pass
> the virtual interface pointer.
>
> which also touches, besides the API mac80211 tkip handling, iwl-agn as well
> as b43.

Yeah, I backed it out right away and told the authors about it, but
didn't push the stable-queue changes out, sorry about that.

greg k-h
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