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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 2EDFFC43603 for ; Thu, 5 Dec 2019 00:36:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10B242077B for ; Thu, 5 Dec 2019 00:36:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728542AbfLEAgl (ORCPT ); Wed, 4 Dec 2019 19:36:41 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:38198 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728011AbfLEAgk (ORCPT ); Wed, 4 Dec 2019 19:36:40 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id C4EA114F1EDA3; Wed, 4 Dec 2019 16:36:39 -0800 (PST) Date: Wed, 04 Dec 2019 16:36:39 -0800 (PST) Message-Id: <20191204.163639.1986460530334668542.davem@davemloft.net> To: jonathan.lemon@gmail.com Cc: netdev@vger.kernel.org, kernel-team@fb.com, brouer@redhat.com, grygorii.strashko@ti.com Subject: Re: [net PATCH] xdp: obtain the mem_id mutex before trying to remove an entry. From: David Miller In-Reply-To: <20191203220114.1524992-1-jonathan.lemon@gmail.com> References: <20191203220114.1524992-1-jonathan.lemon@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 04 Dec 2019 16:36:40 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jonathan Lemon Date: Tue, 3 Dec 2019 14:01:14 -0800 > A lockdep splat was observed when trying to remove an xdp memory > model from the table since the mutex was obtained when trying to > remove the entry, but not before the table walk started: > > Fix the splat by obtaining the lock before starting the table walk. > > Fixes: c3f812cea0d7 ("page_pool: do not release pool until inflight == 0.") > Reported-by: Grygorii Strashko > Signed-off-by: Jonathan Lemon Applied, and since this fixes a bug fix that went back to v5.3 in -stable I will queue it there as well. Thanks.