From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753967AbbAUTDA (ORCPT ); Wed, 21 Jan 2015 14:03:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45066 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753330AbbAUTCW (ORCPT ); Wed, 21 Jan 2015 14:02:22 -0500 From: Vitaly Kuznetsov To: "K. Y. Srinivasan" , devel@linuxdriverproject.org Cc: Haiyang Zhang , linux-kernel@vger.kernel.org, Dexuan Cui Subject: [PATCH 1/3] Drivers: hv: vmbus: avoid double kfree for device_obj Date: Wed, 21 Jan 2015 20:02:07 +0100 Message-Id: <1421866929-20167-2-git-send-email-vkuznets@redhat.com> In-Reply-To: <1421866929-20167-1-git-send-email-vkuznets@redhat.com> References: <1421866929-20167-1-git-send-email-vkuznets@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On driver shutdown device_obj is being freed twice: 1) In vmbus_free_channels() 2) vmbus_device_release() (which is being triggered by device_unregister() in vmbus_device_unregister(). This double kfree leads to the following sporadic crash on driver unload: [ 23.469876] general protection fault: 0000 [#1] SMP [ 23.470036] Modules linked in: hv_vmbus(-) [ 23.470036] CPU: 2 PID: 213 Comm: rmmod Not tainted 3.19.0-rc5_bug923184+ #488 [ 23.470036] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 23.470036] task: ffff880036ef1cb0 ti: ffff880036ce8000 task.ti: ffff880036ce8000 [ 23.470036] RIP: 0010:[] [] __kmalloc_node_track_caller+0xdb/0x1e0 [ 23.470036] RSP: 0018:ffff880036cebcc8 EFLAGS: 00010246 ... When this crash does not happen on driver unload the similar one is expected if we try to load hv_vmbus again. Remove kfree from vmbus_free_channels() as freeing it from vmbus_device_release() seems right. Signed-off-by: Vitaly Kuznetsov --- drivers/hv/channel_mgmt.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 877a944..0141a3d 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -259,7 +259,6 @@ void vmbus_free_channels(void) list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { vmbus_device_unregister(channel->device_obj); - kfree(channel->device_obj); free_channel(channel); } } -- 1.9.3