Return-path: Received: from mail-ob0-f175.google.com ([209.85.214.175]:53771 "EHLO mail-ob0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751583AbaCJHDx convert rfc822-to-8bit (ORCPT ); Mon, 10 Mar 2014 03:03:53 -0400 Received: by mail-ob0-f175.google.com with SMTP id uy5so6530293obc.6 for ; Mon, 10 Mar 2014 00:03:53 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1394174912.4192.9.camel@dubbel> References: <1394017904-4012-1-git-send-email-luca@coelho.fi> <1394017904-4012-3-git-send-email-luca@coelho.fi> <1394174912.4192.9.camel@dubbel> Date: Mon, 10 Mar 2014 08:03:53 +0100 Message-ID: (sfid-20140310_080356_781153_F7D72DB7) Subject: Re: [PATCH v5 2/3] mac80211: implement chanctx reservation From: Michal Kazior To: Luca Coelho Cc: linux-wireless , Johannes Berg , sw@simonwunderlich.de, "Otcheretianski, Andrei" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 7 March 2014 07:48, Luca Coelho wrote: > On Wed, 2014-03-05 at 13:04 +0100, Michal Kazior wrote: >> On 5 March 2014 12:11, Luca Coelho wrote: >> >> [...] >> >> > + /* unref our reservation before assigning */ >> > + ctx->refcount--; >> > + sdata->reserved_chanctx = NULL; >> > + ret = ieee80211_assign_vif_chanctx(sdata, ctx); >> > + if (ret) { >> > + /* if assign fails refcount stays the same */ >> > + if (ctx->refcount == 0) >> > + ieee80211_free_chanctx(local, ctx); >> > + goto out_wake; >> > + } >> >> This actually won't work if there are AP VLANs (I noticed that yesterday). >> >> You can't call ieee80211_vif_copy_chanctx_to_vlans() here due to >> current locking requirements. I have a patch for that though ;-) I'll >> send it soon. > > How is this related to this patch? > > Anyway, good to know that you have fixed it. :) If you re-assign a chanctx of an AP that has VLANs you leave VLANs with the old chanctx pointer. Those pointers should be updated or else you'll end up dereferencing an invalid pointer. Michał