From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031278AbWKUSen (ORCPT ); Tue, 21 Nov 2006 13:34:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031279AbWKUSem (ORCPT ); Tue, 21 Nov 2006 13:34:42 -0500 Received: from crystal.sipsolutions.net ([195.210.38.204]:15799 "EHLO sipsolutions.net") by vger.kernel.org with ESMTP id S1031278AbWKUSem (ORCPT ); Tue, 21 Nov 2006 13:34:42 -0500 Subject: Re: RFC/T: Trial fix for the bcm43xx - wpa_supplicant - NetworkManager deadlock From: Johannes Berg To: Larry Finger Cc: Ray Lee , Dan Williams , Broadcom Linux , LKML In-Reply-To: <45633FF8.6010209@lwfinger.net> References: <4561DBE0.2060908@lwfinger.net> <45628C05.405@madrabbit.org> <45633FF8.6010209@lwfinger.net> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-MJTypfeyva44t17NiCeJ" Date: Tue, 21 Nov 2006 19:32:42 +0100 Message-Id: <1164133962.3631.14.camel@johannes.berg> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-MJTypfeyva44t17NiCeJ Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2006-11-21 at 12:05 -0600, Larry Finger wrote: > Although my understanding of locking has been shown to be deficient, it l= ooks to me as if the > deadlock involves a WX call while a scan is in progress. The following pa= tch uses > mutex_trylock rather than mutex_lock so that WX calls are rejected if the= lock is already held. > Please try this patch with wpa_supplicant and NetworkManager both running= . I have tested it with > wpa_supplicant alone. I don't think this is the right thing to do. This cannot be causing the deadlock as for a deadlock you need (at least) two locks. Now, since any calls from userspace to d80211 acquire the mutex first, they should be fine. They also both acquire the rtnl lock first. The deadlock must be somewhere deeper. Can we run this with lockdep enabled? Might give us a hint before we dig out all the used locks here... johannes --=-MJTypfeyva44t17NiCeJ Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iD8DBQBFY0ZI/ETPhpq3jKURAq+DAKCY/nJiUTMh3ZXuz46Gz2PG3h6xEQCgmDoj PWwxEJpBueqEETy0BEMd0oM= =pRQH -----END PGP SIGNATURE----- --=-MJTypfeyva44t17NiCeJ--