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 28937C3F6B0 for ; Mon, 22 Aug 2022 10:15:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232473AbiHVKPm (ORCPT ); Mon, 22 Aug 2022 06:15:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234616AbiHVKPb (ORCPT ); Mon, 22 Aug 2022 06:15:31 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 006B5EE08 for ; Mon, 22 Aug 2022 03:15:29 -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 ams.source.kernel.org (Postfix) with ESMTPS id 9EC43B80EFE for ; Mon, 22 Aug 2022 10:15:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5956C433C1; Mon, 22 Aug 2022 10:15:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661163327; bh=rW4OBC07jkas+k1WxD3RIgWJ3+Ttwd5CNNtpJoDQwL8=; h=Subject:To:Cc:From:Date:From; b=hka7CI4ao+EUP+McX62mEvXrBDa5sNyeCZz9bynjzlwQbQBrTPkEGQyHsO0xLxV2X 7iSu7IeMBsM4+Zcu5ofPs55/twhqed7rH0LFMfP8cTkV4c45b0FgFsU+y+km4GWHzf 50EPct+96UfgvPSSvOGgeM4uJC+XZ+fApzfy9e3s= Subject: FAILED: patch "[PATCH] iavf: Fix deadlock in initialization" failed to apply to 5.4-stable tree To: ivecera@redhat.com, anthony.l.nguyen@intel.com, konrad0.jankowski@intel.com Cc: From: Date: Mon, 22 Aug 2022 12:15:24 +0200 Message-ID: <166116332464154@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From cbe9e51126305832cf407ee6bb556ce831488ffe Mon Sep 17 00:00:00 2001 From: Ivan Vecera Date: Mon, 8 Aug 2022 19:58:45 +0200 Subject: [PATCH] iavf: Fix deadlock in initialization Fix deadlock that occurs when iavf interface is a part of failover configuration. 1. Mutex crit_lock is taken at the beginning of iavf_watchdog_task() 2. Function iavf_init_config_adapter() is called when adapter state is __IAVF_INIT_CONFIG_ADAPTER 3. iavf_init_config_adapter() calls register_netdevice() that emits NETDEV_REGISTER event 4. Notifier function failover_event() then calls net_failover_slave_register() that calls dev_open() 5. dev_open() calls iavf_open() that tries to take crit_lock in end-less loop Stack trace: ... [ 790.251876] usleep_range_state+0x5b/0x80 [ 790.252547] iavf_open+0x37/0x1d0 [iavf] [ 790.253139] __dev_open+0xcd/0x160 [ 790.253699] dev_open+0x47/0x90 [ 790.254323] net_failover_slave_register+0x122/0x220 [net_failover] [ 790.255213] failover_slave_register.part.7+0xd2/0x180 [failover] [ 790.256050] failover_event+0x122/0x1ab [failover] [ 790.256821] notifier_call_chain+0x47/0x70 [ 790.257510] register_netdevice+0x20f/0x550 [ 790.258263] iavf_watchdog_task+0x7c8/0xea0 [iavf] [ 790.259009] process_one_work+0x1a7/0x360 [ 790.259705] worker_thread+0x30/0x390 To fix the situation we should check the current adapter state after first unsuccessful mutex_trylock() and return with -EBUSY if it is __IAVF_INIT_CONFIG_ADAPTER. Fixes: 226d528512cf ("iavf: fix locking of critical sections") Signed-off-by: Ivan Vecera Tested-by: Konrad Jankowski Signed-off-by: Tony Nguyen diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index 95d4348e7579..f39440ad5c50 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -4088,8 +4088,17 @@ static int iavf_open(struct net_device *netdev) return -EIO; } - while (!mutex_trylock(&adapter->crit_lock)) + while (!mutex_trylock(&adapter->crit_lock)) { + /* If we are in __IAVF_INIT_CONFIG_ADAPTER state the crit_lock + * is already taken and iavf_open is called from an upper + * device's notifier reacting on NETDEV_REGISTER event. + * We have to leave here to avoid dead lock. + */ + if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER) + return -EBUSY; + usleep_range(500, 1000); + } if (adapter->state != __IAVF_DOWN) { err = -EBUSY;