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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F838C04AB4 for ; Fri, 17 May 2019 09:33:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 585912082E for ; Fri, 17 May 2019 09:33:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728143AbfEQJdo (ORCPT ); Fri, 17 May 2019 05:33:44 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:33524 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727758AbfEQJdo (ORCPT ); Fri, 17 May 2019 05:33:44 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 2A2F380398; Fri, 17 May 2019 11:33:32 +0200 (CEST) Date: Fri, 17 May 2019 11:33:41 +0200 From: Pavel Machek To: Claudiu Manoil Cc: Pavel Machek , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , "David S. Miller" , Sasha Levin , "alexandre.belloni@bootlin.com" Subject: Re: [PATCH 4.19 042/113] ocelot: Dont sleep in atomic context (irqs_disabled()) Message-ID: <20190517093341.GA18565@amd> References: <20190515090652.640988966@linuxfoundation.org> <20190515090656.813206864@linuxfoundation.org> <20190517081642.GC17012@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="J/dobhs11T7y2rNN" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org --J/dobhs11T7y2rNN Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > >On Wed 2019-05-15 12:55:33, Greg Kroah-Hartman wrote: > >> [ Upstream commit a8fd48b50deaa20808bbf0f6685f6f1acba6a64c ] > >> > >> Preemption disabled at: > >> [] dev_set_rx_mode+0x1c/0x38 > >> Call trace: > >> [] dump_backtrace+0x0/0x3d0 > >> [] show_stack+0x14/0x20 > >> [] dump_stack+0xac/0xe4 > >> [] ___might_sleep+0x164/0x238 > >> [] __might_sleep+0x50/0x88 > >> [] kmem_cache_alloc+0x17c/0x1d0 > >> [] ocelot_set_rx_mode+0x108/0x188 > >[mscc_ocelot_common] > >> [] __dev_set_rx_mode+0x58/0xa0 > >> [] dev_set_rx_mode+0x24/0x38 > >> > >> Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support") > > > >Is it right fix? Warning is gone, but now allocation is more likely to > >fail, causing mc_add() to fail under memory pressure. > > >=20 > So far this contributes to fixing a kernel hang issue, seen occasionally > when the switch interfaces were brought up. > Other than that I would look into improving this code. > It looks suboptimal at least. Do we really need to allocate whole > struct netdev_hw_addr elements? Can the allocation size be reduced? > What about pre-allocating enough room for ha elements outside the > atomic context (set_rx_mode() in this case)? Pre-allocating the elements sounds like a obvious solution, yes. Best regards, Pavel --=20 DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --J/dobhs11T7y2rNN Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlzef/UACgkQMOfwapXb+vJjGgCgstxXfIUGi5SKgeRmDcJmlcjT VUUAn3UEZsjB0dizYH96Q9/AOiF/k8I2 =PdRN -----END PGP SIGNATURE----- --J/dobhs11T7y2rNN--