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 3B5FAC77B61 for ; Tue, 28 Mar 2023 15:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233786AbjC1PEM (ORCPT ); Tue, 28 Mar 2023 11:04:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233791AbjC1PEL (ORCPT ); Tue, 28 Mar 2023 11:04:11 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02AE9A5ED for ; Tue, 28 Mar 2023 08:03:01 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 24555617F1 for ; Tue, 28 Mar 2023 15:03:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 316A1C433EF; Tue, 28 Mar 2023 15:02:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680015779; bh=nzBpbAX6GUHoyDmkTBMF6QoSW4vYSZx7G+9QiY7sN40=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zz4S2Kz5v4P7a56hvUX4xu/RFnnAXO0+1rd2FLJalYnq0sBrgJNuGCdibpKb3cVPr kYFneWO0o95oxVhs3ZFPpIWDWw7EE3Q9ADsAme4ZmFv6wuT32fZCYdOWYVFLmp+bUJ +oJz90lLXuJ5Cv6pwqcWXQbHcD2gKHbUsPqvckdw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Corinna Vinschen , Lin Ma , Jacob Keller , Simon Horman , Rafal Romanowski , Tony Nguyen Subject: [PATCH 6.1 172/224] igb: revert rtnl_lock() that causes deadlock Date: Tue, 28 Mar 2023 16:42:48 +0200 Message-Id: <20230328142624.544319515@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230328142617.205414124@linuxfoundation.org> References: <20230328142617.205414124@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Lin Ma commit 65f69851e44d71248b952a687e44759a7abb5016 upstream. The commit 6faee3d4ee8b ("igb: Add lock to avoid data race") adds rtnl_lock to eliminate a false data race shown below (FREE from device detaching) | (USE from netdev core) igb_remove | igb_ndo_get_vf_config igb_disable_sriov | vf >= adapter->vfs_allocated_count? kfree(adapter->vf_data) | adapter->vfs_allocated_count = 0 | | memcpy(... adapter->vf_data[vf] The above race will never happen and the extra rtnl_lock causes deadlock below [ 141.420169] [ 141.420672] __schedule+0x2dd/0x840 [ 141.421427] schedule+0x50/0xc0 [ 141.422041] schedule_preempt_disabled+0x11/0x20 [ 141.422678] __mutex_lock.isra.13+0x431/0x6b0 [ 141.423324] unregister_netdev+0xe/0x20 [ 141.423578] igbvf_remove+0x45/0xe0 [igbvf] [ 141.423791] pci_device_remove+0x36/0xb0 [ 141.423990] device_release_driver_internal+0xc1/0x160 [ 141.424270] pci_stop_bus_device+0x6d/0x90 [ 141.424507] pci_stop_and_remove_bus_device+0xe/0x20 [ 141.424789] pci_iov_remove_virtfn+0xba/0x120 [ 141.425452] sriov_disable+0x2f/0xf0 [ 141.425679] igb_disable_sriov+0x4e/0x100 [igb] [ 141.426353] igb_remove+0xa0/0x130 [igb] [ 141.426599] pci_device_remove+0x36/0xb0 [ 141.426796] device_release_driver_internal+0xc1/0x160 [ 141.427060] driver_detach+0x44/0x90 [ 141.427253] bus_remove_driver+0x55/0xe0 [ 141.427477] pci_unregister_driver+0x2a/0xa0 [ 141.428296] __x64_sys_delete_module+0x141/0x2b0 [ 141.429126] ? mntput_no_expire+0x4a/0x240 [ 141.429363] ? syscall_trace_enter.isra.19+0x126/0x1a0 [ 141.429653] do_syscall_64+0x5b/0x80 [ 141.429847] ? exit_to_user_mode_prepare+0x14d/0x1c0 [ 141.430109] ? syscall_exit_to_user_mode+0x12/0x30 [ 141.430849] ? do_syscall_64+0x67/0x80 [ 141.431083] ? syscall_exit_to_user_mode_prepare+0x183/0x1b0 [ 141.431770] ? syscall_exit_to_user_mode+0x12/0x30 [ 141.432482] ? do_syscall_64+0x67/0x80 [ 141.432714] ? exc_page_fault+0x64/0x140 [ 141.432911] entry_SYSCALL_64_after_hwframe+0x72/0xdc Since the igb_disable_sriov() will call pci_disable_sriov() before releasing any resources, the netdev core will synchronize the cleanup to avoid any races. This patch removes the useless rtnl_(un)lock to guarantee correctness. CC: stable@vger.kernel.org Fixes: 6faee3d4ee8b ("igb: Add lock to avoid data race") Reported-by: Corinna Vinschen Link: https://lore.kernel.org/intel-wired-lan/ZAcJvkEPqWeJHO2r@calimero.vinschen.de/ Signed-off-by: Lin Ma Tested-by: Corinna Vinschen Reviewed-by: Jacob Keller Reviewed-by: Simon Horman Tested-by: Rafal Romanowski Signed-off-by: Tony Nguyen Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/intel/igb/igb_main.c | 2 -- 1 file changed, 2 deletions(-) --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -3841,9 +3841,7 @@ static void igb_remove(struct pci_dev *p igb_release_hw_control(adapter); #ifdef CONFIG_PCI_IOV - rtnl_lock(); igb_disable_sriov(pdev); - rtnl_unlock(); #endif unregister_netdev(netdev);