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 69EB1C25B07 for ; Thu, 11 Aug 2022 21:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233973AbiHKVl6 (ORCPT ); Thu, 11 Aug 2022 17:41:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230422AbiHKVl5 (ORCPT ); Thu, 11 Aug 2022 17:41:57 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1F9C9F0E9 for ; Thu, 11 Aug 2022 14:41:56 -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 85533CE2107 for ; Thu, 11 Aug 2022 21:41:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 334E3C433D6; Thu, 11 Aug 2022 21:41:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660254112; bh=sHLc73KXR0K1Nu0toL5g8k604GueGzA6AHIHEoqrmAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EKcrpUtm5/KyTu5jd3Z8mzgNJjx3rqd4Z//uMXXc5qz1q2JGyTMBo+D9zjdHZVh3B ESB+tSIci7F7iVQmHJ5aQo06nMgSqkUMysFiHMIogi3+qXSNTDeCDTL3YE/OblaAis oV0BPaOD6wZ9Iumn4AaacvRCxGVL3mLb2RiE1mMOaCyYNgqvjW08blNbmWqhX+54PH YlfabiV86h6HiKxWp/uiZWuu+KcmlK+powNLWTagwOZ87FBOOCYvTYfZHC13Er9z+7 2ISkUSptpXLA0I6+H1VIPGmLNRB3RqB3ECBwnje1lIDXXd8NghBWEWimsYs5o1gVm5 DQVKKK0kdWriA== From: James Hogan To: Vinicius Costa Gomes Cc: Vinicius Costa Gomes , Paul Menzel , Tony Nguyen , Jesse Brandeburg , netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org, Sasha Neftin , Aleksandr Loktionov Subject: Re: [WIP v2] igc: fix deadlock caused by taking RTNL in RPM resume path Date: Thu, 11 Aug 2022 22:41:48 +0100 Message-ID: <4759452.31r3eYUQgx@saruman> In-Reply-To: <20220811202524.78323-1-vinicius.gomes@intel.com> References: <20220811151342.19059-1-vinicius.gomes@intel.com> <20220811202524.78323-1-vinicius.gomes@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thursday, 11 August 2022 21:25:24 BST Vinicius Costa Gomes wrote: > It was reported a RTNL deadlock in the igc driver that was causing > problems during suspend/resume. > > The solution is similar to commit ac8c58f5b535 ("igb: fix deadlock > caused by taking RTNL in RPM resume path"). > > Reported-by: James Hogan > Signed-off-by: Vinicius Costa Gomes > --- > Sorry for the noise earlier, my kernel config didn't have runtime PM > enabled. Thanks for looking into this. This is identical to the patch I've been running for the last week. The deadlock is avoided, however I now occasionally see an assertion from netif_set_real_num_tx_queues due to the lock not being taken in some cases via the runtime_resume path, and a suspicious rcu_dereference_protected() warning (presumably due to the same issue of the lock not being taken). See here for details: https://lore.kernel.org/netdev/4765029.31r3eYUQgx@saruman/ Cheers James