linux-wireless.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Michael Buesch <mb@bu3sch.de>
To: Larry Finger <larry.finger@lwfinger.net>
Cc: bcm43xx-dev@lists.berlios.de, linux-wireless@vger.kernel.org
Subject: Re: [RFC/T V2] b43: Fix Radio On/Off LED action
Date: Wed, 28 Nov 2007 17:46:55 +0100	[thread overview]
Message-ID: <200711281746.56069.mb@bu3sch.de> (raw)
In-Reply-To: <474D9A46.1020300@lwfinger.net>

On Wednesday 28 November 2007 17:41:42 Larry Finger wrote:
> Michael Buesch wrote:
> > 
> > I think it's a different bug. The backtrace seems corrupted.
> > 
> > Can you try this patch? There is some circular locking in rfkill.
> 
> I still get circular locking. The dump is

Ok.

b43 init:
	mutex_lock(wl->mutex)
	rfkill_init()
		mutex_lock(rfkill->mutex)

in operation:
	rfkill poll (no locks held)
	calls into rfkill
	mutex_lock(rfkill->mutex)
	b43_rfkill_soft_toggle()
		mutex_lock(wl->mutex)

As you can see the lock ordering of the two mutexes
is different. The problem is that we cannot easily drop
the wl->mutex on b43 init, as that would introduce some
race conditions. This is specific to b43 and rt2x00 most
likely doesn't have this requirement.
I'm not sure how to properly fix this.

-- 
Greetings Michael.

  reply	other threads:[~2007-11-28 16:48 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-27 16:03 [RFC/T] b43: Fix Radio On/Off LED action Larry Finger
2007-11-27 16:13 ` Michael Buesch
2007-11-27 16:28   ` Larry Finger
2007-11-27 17:05     ` Michael Buesch
2007-11-27 18:29       ` Ehud Gavron
2007-11-27 20:02   ` [RFC/T V2] " Larry Finger
2007-11-27 20:20     ` Michael Buesch
2007-11-27 21:22       ` Larry Finger
2007-11-28 14:11         ` Michael Buesch
2007-11-28 15:05           ` Larry Finger
2007-11-28 16:13             ` Michael Buesch
2007-11-28 16:41               ` Larry Finger
2007-11-28 16:46                 ` Michael Buesch [this message]
2007-11-28 17:08                   ` Larry Finger

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=200711281746.56069.mb@bu3sch.de \
    --to=mb@bu3sch.de \
    --cc=bcm43xx-dev@lists.berlios.de \
    --cc=larry.finger@lwfinger.net \
    --cc=linux-wireless@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).