From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161597AbcA1ExX (ORCPT ); Wed, 27 Jan 2016 23:53:23 -0500 Received: from p3plsmtps2ded03.prod.phx3.secureserver.net ([208.109.80.60]:47690 "EHLO p3plsmtps2ded03.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161534AbcA1ExU (ORCPT ); Wed, 27 Jan 2016 23:53:20 -0500 x-originating-ip: 72.167.245.219 From: "K. Y. Srinivasan" To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com Cc: "K. Y. Srinivasan" Subject: [PATCH V2 02/13] Drivers: hv: vmbus: avoid infinite loop in init_vp_index() Date: Wed, 27 Jan 2016 22:29:34 -0800 Message-Id: <1453962585-32069-2-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1453962585-32069-1-git-send-email-kys@microsoft.com> References: <1453962559-32028-1-git-send-email-kys@microsoft.com> <1453962585-32069-1-git-send-email-kys@microsoft.com> X-CMAE-Envelope: MS4wfK31du4Hx6Kc/rJY+3vvGGkL3ACPwcG0zWDQeY3c20Cx6OBFqxy4TWdfYy7eIlO2P8ut8TnFfXoiKI4ijVBNqZ1WWIMpSGGxxuDlVbZgokNq/3ND4wy8 yKLH1VXoMvx7z4nElxpCaWTYwj3p5OVxeyotz/5ewch7mBuldz/8fDUnRNCjn8Jiw11aMHVJydTp1E4LYXrVwBhfYcnegXOiijr4QXDUQM3BK/g3uwRjp91a K8liVxy3JafArHrdFjfn1NcIDGOv1ofJdQpbLZvNZ8o9WL9tufMdJSf0x65SOAD/F0I72wJ45zwAuJha3kGyYhd1hSe7v1lU4vZ39T/on4H9cnpGCt/Nc/Jm kmN0XnkzEHNUMT0eafQUl3jQl491LgxS83bf4e3su06twoThtW7IUZmIP6tvOOpAPGYLLgtx Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vitaly Kuznetsov When we pick a CPU to use for a new subchannel we try find a non-used one on the appropriate NUMA node, we keep track of them with the primary->alloced_cpus_in_node mask. Under normal circumstances we don't run out of available CPUs but it is possible when we we don't initialize some cpus in Linux, e.g. when we boot with 'nr_cpus=' limitation. Avoid the infinite loop in init_vp_index() by checking that we still have non-used CPUs in the alloced_cpus_in_node mask and resetting it in case we don't. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan --- drivers/hv/channel_mgmt.c | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 107d72f..af1d82e 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -549,6 +549,17 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) cpumask_of_node(primary->numa_node)); cur_cpu = -1; + + /* + * Normally Hyper-V host doesn't create more subchannels than there + * are VCPUs on the node but it is possible when not all present VCPUs + * on the node are initialized by guest. Clear the alloced_cpus_in_node + * to start over. + */ + if (cpumask_equal(&primary->alloced_cpus_in_node, + cpumask_of_node(primary->numa_node))) + cpumask_clear(&primary->alloced_cpus_in_node); + while (true) { cur_cpu = cpumask_next(cur_cpu, &available_mask); if (cur_cpu >= nr_cpu_ids) { -- 1.7.4.1