Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751718AbdIRDzZ (ORCPT ); Sun, 17 Sep 2017 23:55:25 -0400 Received: from a2nlsmtp01-05.prod.iad2.secureserver.net ([198.71.225.49]:36448 "EHLO a2nlsmtp01-05.prod.iad2.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751462AbdIRDzW (ORCPT ); Sun, 17 Sep 2017 23:55:22 -0400 x-originating-ip: 107.180.71.197 From: kys@exchange.microsoft.com To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com, leann.ogasawara@canonical.com, marcelo.cerri@canonical.com, sthemmin@microsoft.com Cc: Dexuan Cui , "K . Y . Srinivasan" , Haiyang Zhang Subject: [PATCH V2 1/4] vmbus: don't acquire the mutex in vmbus_hvsock_device_unregister() Date: Sun, 17 Sep 2017 20:54:16 -0700 Message-Id: <20170918035419.11062-1-kys@exchange.microsoft.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170918034955.10913-1-kys@exchange.microsoft.com> References: <20170918034955.10913-1-kys@exchange.microsoft.com> Reply-To: kys@microsoft.com X-CMAE-Envelope: MS4wfGRgUMq8HrqUV6QHfygc25oglHE30+lgwlpD8Mq8cpY2STb4ER5zJRMW8uPRuJz1/mCmDdfWxWVfIgbH/vki/Ic7NWhVAgcw3NCgS7P3+/h6rA+DXPcg EOTeWjmvK63002sEk9B7eJ61YJZ6wFv8Dg2D4oj6wkxzLi3+XbsRmhbljcn5V88eqZfu3VBLRElvXovdPs6Lvvon2LHRXCsUWF+ixsjDkTjeQpEaseoxhJKX +l2NyHRmlDvnKZUB3M0wimV4pyVMWlndPmOHRhF8rqerLCnscnXl+zrWiKLYa6L51v+805KJo6x8LbFDGxvZih9WvaFwGhiKg9DDsNhsyclsDqXtvgZgA7fs AoWbX4+0OEUwSFgGpE2JFsXc5cg196FljNDTb+VOHE695fbabAUv8M9VlHxwiRmHjgiOL8sgohBJ7PsEBTjTZ73gRnwqVTHebmwoNKnxXg7sDwgER4NhafT2 SsYRFbxFBECRKPHb2ttdFguZG0B7dcd/4GGMu7+VlkbdhTNLyQsFNDvrxpWgGUj4Zs1KRoVorHntoRiUN18LCTclWmF+hotbLy80y/ushhXjxjBf9X7ziog6 hFSwCqoXwBEkbgryPrBIUvIs Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1348 Lines: 40 From: Dexuan Cui Due to commit 54a66265d675 ("Drivers: hv: vmbus: Fix rescind handling"), we need this patch to resolve the below deadlock: after we get the mutex in vmbus_hvsock_device_unregister() and call vmbus_device_unregister() -> device_unregister() -> ... -> device_release() -> vmbus_device_release(), we'll get a deadlock, because vmbus_device_release() tries to get the same mutex. Signed-off-by: Dexuan Cui Cc: K. Y. Srinivasan Cc: Haiyang Zhang Cc: Stephen Hemminger Signed-off-by: K. Y. Srinivasan --- drivers/hv/channel_mgmt.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 968af173c4c1..624d815745e4 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -945,14 +945,10 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr) void vmbus_hvsock_device_unregister(struct vmbus_channel *channel) { - mutex_lock(&vmbus_connection.channel_mutex); - BUG_ON(!is_hvsock_channel(channel)); channel->rescind = true; vmbus_device_unregister(channel->device_obj); - - mutex_unlock(&vmbus_connection.channel_mutex); } EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister); -- 2.14.1