Return-path: Received: from s3.sipsolutions.net ([144.76.63.242]:37322 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932960AbeFTIpR (ORCPT ); Wed, 20 Jun 2018 04:45:17 -0400 Message-ID: <1529481305.3130.3.camel@sipsolutions.net> (sfid-20180620_104525_089072_64E1EAB8) Subject: Re: [PATCH] mac80211: Fix oops in ieee80211_tx_control_port From: Johannes Berg To: Arend van Spriel , Denis Kenzior , linux-wireless@vger.kernel.org Date: Wed, 20 Jun 2018 09:55:05 +0200 In-Reply-To: <5B2A0843.9080902@broadcom.com> (sfid-20180620_095446_031821_FD96522E) References: <20180619153950.28903-1-denkenz@gmail.com> <5B2A0772.4060200@broadcom.com> <1529481182.3130.2.camel@sipsolutions.net> <5B2A0843.9080902@broadcom.com> (sfid-20180620_095446_031821_FD96522E) Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 2018-06-20 at 09:54 +0200, Arend van Spriel wrote: > On 6/20/2018 9:53 AM, Johannes Berg wrote: > > On Wed, 2018-06-20 at 09:51 +0200, Arend van Spriel wrote: > > > On 6/19/2018 5:39 PM, Denis Kenzior wrote: > > > > On pre-emption enabled kernels the following oops was being seen due > > > > to missing local_bh_disable/local_bh_enable calls. mac80211 assumes > > > > that pre-emption is disabled in the data path. > > > > > > No sure if "assumes" is the right term here. It seems like it is > > > required and there is probably a good reason for that. Would be nice to > > > know what that reason is. > > > > It's using per-CPU data. > > Hence the smp_processor_id() call which Denis mentioned in the bug report? Yeah, I think that's an implementation detail thereof. johannes