From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94F3EC433EF for ; Tue, 24 May 2022 07:28:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235249AbiEXH2A (ORCPT ); Tue, 24 May 2022 03:28:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbiEXH0b (ORCPT ); Tue, 24 May 2022 03:26:31 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 537251145D; Tue, 24 May 2022 00:26:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id B1E04CE1A54; Tue, 24 May 2022 07:26:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1474CC34100; Tue, 24 May 2022 07:26:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653377186; bh=bIROaGOZbF93Xt0aHUg1j/Xrg0023fKyXPwCzZwVCaQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cK34n+iF/tkd+qGzXLOY68MrWM0kGjGMv7m8Tmu9tc6YmeNSSr5dDp3yugtJvZyqh 1HyARCzxvwupVDVgf+4eMX37hSuwlEEOrpOT4GfxITMMG28M0XeR3H3m2Gry9UFF5A fDwsr2eK6aqYAx784UpRUf9Mc6bfEbRUCZMno0zf+cl20DVtOSB5MRZW+WF4M82V2L irGYe4xG9Zhx44jfeueCvBvVVCrBx3jCBUv52rbzkVY1HPYpvMVazxy8qQaMDsW93/ 7xD3Qh1Nyi/cvzsp4Q0yRVngUR9NshAdEOGoVv8h5sPNKnCKdZOQikB8mhRE8CvgoO eRpJSGrJu50Bg== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1ntOvv-0001yU-4e; Tue, 24 May 2022 09:26:23 +0200 Date: Tue, 24 May 2022 09:26:23 +0200 From: Johan Hovold To: Kalle Valo Cc: Johan Hovold , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , ath11k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC] ath11k: fix netdev open race Message-ID: References: <20220517103436.15867-1-johan+linaro@kernel.org> <875ylwysoy.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <875ylwysoy.fsf@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 23, 2022 at 10:06:37PM +0300, Kalle Valo wrote: > Johan Hovold writes: > > > On Tue, May 17, 2022 at 12:34:36PM +0200, Johan Hovold wrote: > >> Make sure to allocate resources needed before registering the device. > >> > >> This specifically avoids having a racing open() trigger a BUG_ON() in > >> mod_timer() when ath11k_mac_op_start() is called before the > >> mon_reap_timer as been set up. > >> > >> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") > >> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend") > >> Signed-off-by: Johan Hovold > >> --- > > > > For completeness: > > > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3 > > Thanks, added in the pending branch. > > You submitted this as RFC but do you mind if I apply this anyway? The > patch looks good and passes my tests. But I do wonder why I haven't seen > the crash... If it looks good to you then please do apply it. I was just worried that there may be some subtle reason for why ath11k_dp_pdev_alloc() was called after netdev registration in the first place and that it might need to be split up so that for example ath11k_dp_rx_pdev_mon_attach() isn't called until after registration. I did not see this issue with next-20220310, but I hit it on every probe with next-20220511. Perhaps some timing changed in between. Here's the backtrace for completeness in case someone else starts hitting this and searches the archives: [ 51.346947] kernel BUG at kernel/time/timer.c:990! [ 51.346958] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ... [ 51.578225] Call trace: [ 51.583293] __mod_timer+0x298/0x390 [ 51.589518] mod_timer+0x14/0x20 [ 51.595368] ath11k_mac_op_start+0x41c/0x4a0 [ath11k] [ 51.603165] drv_start+0x38/0x60 [mac80211] [ 51.610110] ieee80211_do_open+0x29c/0x7d0 [mac80211] [ 51.617945] ieee80211_open+0x60/0xb0 [mac80211] [ 51.625311] __dev_open+0x100/0x1c0 [ 51.631420] __dev_change_flags+0x194/0x210 [ 51.638214] dev_change_flags+0x24/0x70 [ 51.644646] do_setlink+0x228/0xdb0 [ 51.650723] __rtnl_newlink+0x460/0x830 [ 51.657162] rtnl_newlink+0x4c/0x80 [ 51.663229] rtnetlink_rcv_msg+0x124/0x390 [ 51.669917] netlink_rcv_skb+0x58/0x130 [ 51.676314] rtnetlink_rcv+0x18/0x30 [ 51.682460] netlink_unicast+0x250/0x310 [ 51.688960] netlink_sendmsg+0x19c/0x3e0 [ 51.695458] ____sys_sendmsg+0x220/0x290 [ 51.701938] ___sys_sendmsg+0x7c/0xc0 [ 51.708148] __sys_sendmsg+0x68/0xd0 [ 51.714254] __arm64_sys_sendmsg+0x28/0x40 [ 51.720900] invoke_syscall+0x48/0x120 Johan