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Miller" , Sasha Levin Subject: [PATCH AUTOSEL 4.14 57/67] s390/qeth: fix race in used-buffer accounting Thread-Topic: [PATCH AUTOSEL 4.14 57/67] s390/qeth: fix race in used-buffer accounting Thread-Index: AQHURkMISD0gmpnUIkKWBDwFWp9Z5Q== Date: Fri, 7 Sep 2018 00:38:02 +0000 Message-ID: <20180907003716.57737-57-alexander.levin@microsoft.com> References: <20180907003716.57737-1-alexander.levin@microsoft.com> In-Reply-To: <20180907003716.57737-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY4PR21MB0757;6:Ob0CNpTvbMEQQ9MKZlzy9x7u4uHpu17jZdVuATM36hJ9xXF6D6EQSapwH9rqiQB5gOge/CemrPKzXteQy6Wx4OcZ++lRf8UMf9LJPEsH+Wdgl9q3Os3TWJtmVBKLETKsz7Bf67V3JVDlYoGVCg/466oF4sEBO6Ba0Yha6rlKmS5JcLn4qlEtUkEcJlVnRyupQ9/W/YKq0Nt4GIJ9oOJ+Nbm2AHIx4YKoMd4liKhW43sdW1qyzdfVJI0tsGMVPCKLQaC3KetDwm3kbNkENlxlFe66Zj74qukoPfXuw8I23SvLMYTrdCio2yHMUK9QXRAR+f6eOOM76+whoWmFDUpvnQBpoRYDZI1zuEJCX7Qy+rL/0D9oIazC0gBBoEmMB7I/F40vORcdPFu6N5vY+jI8AqDL7AGhFtVma76FYOAN3EvCOu6V705mra9D5AkDYnC+kwhXUiJBIAu2+Uraerh6BQ==;5:JTd0evklOKgLFeicX7ymruHoOG2cgJEMVypDMFEGyDXYETLwTt5/8VwlHzBmgWsWA5TfwAkWgmSdpCBhxOCohMRsPdLeg1HJ9B2/ztD2YNu6bWTiH+LEla8b3S+jHPoHM6tWqbHqjVb+/FXR7tRvzQsJMEqNoExZcv254F9/00M=;7:R1wd03jdgIRQhBxKQSQstzueQ4C+LMCq5CUYxZW2eFwN1U31d5siAiedsB4OfiAWE8JY7Q1c5+tuq6fql6vepOCmVQoKXz/Ivdgs7CfPZnAf1gw1qMzbQnmpAMqNCIcA7uZbnR75DgT0ag+qNWmsNDgLls8eG+CU03sM+TyATBXmNK7O1REzjpgJ7dKvKw+U++JrAD4e6vds7yCjjzoIaMkci32QggNbVwQC40qC1c7R8fvpCYgyv5/LAikC9Ajl x-ms-office365-filtering-correlation-id: 132386b1-82e1-4e60-b655-08d6145a5265 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0;PCL:0;RULEID:(7020095)(4652040)(8989137)(4534165)(4627221)(201703031133081)(201702281549075)(8990107)(5600074)(711020)(4618075)(2017052603328)(7193020);SRVR:CY4PR21MB0757; x-ms-traffictypediagnostic: CY4PR21MB0757: x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(28532068793085)(89211679590171)(104084551191319); x-ms-exchange-senderadcheck: 1 x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(6040522)(2401047)(8121501046)(5005006)(93006095)(93001095)(3231344)(944501410)(52105095)(2018427008)(3002001)(10201501046)(6055026)(149027)(150027)(6041310)(20161123564045)(20161123558120)(20161123562045)(20161123560045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(201708071742011)(7699049)(76991033);SRVR:CY4PR21MB0757;BCL:0;PCL:0;RULEID:;SRVR:CY4PR21MB0757; x-forefront-prvs: 07880C4932 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39860400002)(366004)(396003)(136003)(346002)(376002)(199004)(189003)(8936002)(3846002)(81166006)(86612001)(6666003)(5250100002)(81156014)(486006)(99286004)(6486002)(106356001)(10290500003)(107886003)(256004)(14444005)(26005)(11346002)(14454004)(446003)(76176011)(6346003)(5660300001)(10090500001)(110136005)(2616005)(66066001)(186003)(476003)(72206003)(2501003)(54906003)(575784001)(316002)(6436002)(86362001)(97736004)(53936002)(22452003)(6506007)(102836004)(8676002)(6512007)(2900100001)(68736007)(305945005)(7736002)(217873002)(6116002)(1076002)(25786009)(2906002)(36756003)(4326008)(105586002)(478600001);DIR:OUT;SFP:1102;SCL:1;SRVR:CY4PR21MB0757;H:CY4PR21MB0776.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-message-info: /NNued+87hzUp5kw7kIFr0wqA6sT9t8bwfxr0VRS3I+rE2IXg7RyPFmSHas4gArfmA4Tc4F6ESn68jFsNHFv7g046XtWfkLvFQzvWg1q4y6Yi+EU5+seQ5GXLFy6IxPeynPniTFXo7vxjXgDdqof/h3BSd75nrjrUe8g7Q6B1W+SpUdhTFrpVwIhB/c1Yq1M30sq13t6GtlStQ0oBVZZRyExLDytfwlZoYq2xsRZs6Z4gg4QdkiQCSDPcFakCAjsWBo5tq1vhB5crhiHwoRkGNP18prActdL0ey9n1lyUU1gqW+RchBVvdUBDw4HQKpV9JDccfLMTa2DNyVpD1f2uUhXISX5CiQ1QJMValSNWVQ= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 132386b1-82e1-4e60-b655-08d6145a5265 X-MS-Exchange-CrossTenant-originalarrivaltime: 07 Sep 2018 00:38:02.6374 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0757 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julian Wiedmann [ Upstream commit a702349a4099cd5a7bab0904689d8e0bf8dcd622 ] By updating q->used_buffers only _after_ do_QDIO() has completed, there is a potential race against the buffer's TX completion. In the unlikely case that the TX completion path wins, qeth_qdio_output_handler() would decrement the counter before qeth_flush_buffers() even incremented it. Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/s390/net/qeth_core_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core= _main.c index 939b5b5e97ef..0a6afd4b283d 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -3507,13 +3507,14 @@ static void qeth_flush_buffers(struct qeth_qdio_out= _q *queue, int index, qdio_flags =3D QDIO_FLAG_SYNC_OUTPUT; if (atomic_read(&queue->set_pci_flags_count)) qdio_flags |=3D QDIO_FLAG_PCI_OUT; + atomic_add(count, &queue->used_buffers); + rc =3D do_QDIO(CARD_DDEV(queue->card), qdio_flags, queue->queue_no, index, count); if (queue->card->options.performance_stats) queue->card->perf_stats.outbound_do_qdio_time +=3D qeth_get_micros() - queue->card->perf_stats.outbound_do_qdio_start_time; - atomic_add(count, &queue->used_buffers); if (rc) { queue->card->stats.tx_errors +=3D count; /* ignore temporary SIGA errors without busy condition */ --=20 2.17.1