Return-path: Received: from mail-wg0-f49.google.com ([74.125.82.49]:34508 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752378AbbAGNwj (ORCPT ); Wed, 7 Jan 2015 08:52:39 -0500 Received: by mail-wg0-f49.google.com with SMTP id n12so1205835wgh.22 for ; Wed, 07 Jan 2015 05:52:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1420638611.3407.14.camel@sipsolutions.net> References: <1419847199-25493-1-git-send-email-arik@wizery.com> <1420541514.1966.16.camel@sipsolutions.net> <1420637871.3407.10.camel@sipsolutions.net> <1420638389.3407.13.camel@sipsolutions.net> <1420638611.3407.14.camel@sipsolutions.net> From: Arik Nemtsov Date: Wed, 7 Jan 2015 15:52:22 +0200 Message-ID: (sfid-20150107_145241_999922_F9BF3ED5) Subject: Re: [PATCH] cfg80211: fix deadlock during reg chan check To: Johannes Berg Cc: "linux-wireless@vger.kernel.org" , "Luis R. Rodriguez" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Jan 7, 2015 at 3:50 PM, Johannes Berg wrote: > On Wed, 2015-01-07 at 15:48 +0200, Arik Nemtsov wrote: >> > >> >> > >> >> >> > Also, the only reason this can happen anyway is when you call "can >> >> >> > beacon" for a station interface - which seems nonsensical. Given that >> >> >> >> >> >> This is not true. This happens with current code for a p2p-go >> >> >> interface during channel validity checks in reg.c. >> >> > >> >> > Not sure I see this? The only thing doing wdev locking is >> >> > cfg80211_go_permissive_chan(), no? And that only for station interfaces. >> >> >> >> cfg80211_go_permissive_chan is called from cfg80211_reg_can_beacon, >> >> currently only for GO interfaces, but for STA also in the future >> >> (hopefully). >> >> The latter is called during channel validity checks for GO. >> > >> > Ok. >> > >> > Should I just apply the patch as it is then? >> >> It fixes a real existing deadlock, so I think so, yea. > > Is it needed on 3.19? Yes, since the channel validity checking is already there. Basically everyone that sets up a GO and has some regulatory change afterwards might deadlock.. Arik