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 C7730C4167B for ; Wed, 8 Nov 2023 16:21:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229720AbjKHQVl (ORCPT ); Wed, 8 Nov 2023 11:21:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230081AbjKHQVk (ORCPT ); Wed, 8 Nov 2023 11:21:40 -0500 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:242:246e::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36BE41FC8 for ; Wed, 8 Nov 2023 08:21:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=yo89hIGpsYEXZ9A+LUgrf3vGs3alPjPbPfbYz5nYKww=; t=1699460498; x=1700670098; b=WLyZ2xQQvfF1wSKPI/nYnBQLuxP02miIIgCnoES4pKRsIT0 AOV+4MEe5Xo9vG+N2E0YQ5eh+GOpclrTaDidStghjrDLN3E6HvOmvrXN2p9ptv5t4XTW3TtbFTUik HTn2GX0CftNEqfzIo/ezIREFr6WmCia3ir2Rb9le4rG3w/HHntNKGAnb89MoVDA8t5qV3K6WfSsta 5trxzxsNzuYHLqpL1BviCTa9ZLqav3Tae03SlWIGaeGtQ0hjkk8EB1CubBOBpeEr/jjuV2PQa8nvV 9NWO/731aXtceWHFJ0hCpxPrFucusLcS5AFPv/ax9zRPac3nqIug9zGNCD1JS06g==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1r0lJA-00000000c3S-1HuQ; Wed, 08 Nov 2023 17:21:36 +0100 Message-ID: <63879a52c28d0140730d8504889c3da17738fe2e.camel@sipsolutions.net> Subject: Re: 6.7.0-rc1 + hacks deadlock bug, wifi netdev delete + cat of debugfs file. From: Johannes Berg To: Ben Greear , linux-wireless Cc: Nicolai Stange Date: Wed, 08 Nov 2023 17:21:35 +0100 In-Reply-To: References: <56d0b043-0585-5380-5703-f25d9a42f39d@candelatech.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-malware-bazaar: not-scanned Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Wed, 2023-11-08 at 16:44 +0100, Johannes Berg wrote: >=20 > > I have been running similar code for...like 15 years, and haven't seen = this particular > > deadlock before, so I think it is at least exacerbated by the locking c= hanges. Or maybe > > I had particularly bad luck yesterday.... >=20 > Oh, it almost certainly did get at least worse or perhaps introduced by > (a) moving everything to a single lock and (b) moving debugfs file > removal under the lock. >=20 FWIW, the debugfs remove was under lock before, but we didn't acquire much locks in the debugfs itself (only sta mtx and only in aql write, and that mutex isn't held in remove) ... So indeed it couldn't happen. I added that to call into drivers with the wiphy mutex though, can't really remove that, I think. johannes