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Thu, 6 Feb 2020 22:01:34 +0000 From: Haiyang Zhang To: sashal@kernel.org, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org Cc: haiyangz@microsoft.com, kys@microsoft.com, sthemmin@microsoft.com, olaf@aepfle.de, vkuznets@redhat.com, davem@davemloft.net, linux-kernel@vger.kernel.org Subject: [PATCH net] hv_netvsc: Fix XDP refcnt for synthetic and VF NICs Date: Thu, 6 Feb 2020 14:01:05 -0800 Message-Id: <1581026465-36161-1-git-send-email-haiyangz@microsoft.com> X-Mailer: git-send-email 1.8.3.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: MWHPR21CA0056.namprd21.prod.outlook.com (2603:10b6:300:db::18) To BL0PR2101MB0897.namprd21.prod.outlook.com (2603:10b6:207:36::18) MIME-Version: 1.0 Received: from linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net (13.77.154.182) by MWHPR21CA0056.namprd21.prod.outlook.com (2603:10b6:300:db::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2729.6 via Frontend Transport; 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Received-SPF: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: QuhZXqwl3tpX0fpcH7k/LC6XiUKVJtrXvuUESao7sqVryrFhPpEYNNVCV9QOPyqr0T3ESHNl/vSx1O8akg5TRN4aAHC01kCR1fKzxtU9NFwCORVNayw/+9AP4Lrr6GiC3LPgk2M7vToQQy0lOWOcAZbfuOHBWx4VSlvdh6+Gj7Cip045+gROO6pnTU449qSKPIUhONBmxt6Zbjp8qBdiNNXAl0KzvcpHFG6lH+Mebrp3MfO9fMT0bOEJlIoZb4+aShxiplYbPUKM+8/aUGTaJnVTyesomN2hNNoIdyREXS/M+gyUIvJgO6a5t3ixFEbdwmTJ69kCKbJl5ObdzCkRUz91w7l72+hUtuIQbQOHuZPSDbchxR6b2glV1uxNQnWmVSXNocIOWRpUhTbPSu872/Ja1/xjqamnUiivdiWP1IywpbvM9dHU0GeXqrf2Azxw X-MS-Exchange-AntiSpam-MessageData: +fhKuXs10z/P/Nr76A8Q0eIYYFIoyJhvSeGs0RHmI1Ax0jkhlS+NxCul8SlrmoC4K++Vu5dAaH3O926S3V8BLS4HPCkKjhZ3H20LpotE0o0LASIdPN+sr33hhyDOuSKTn0/+mnmxeKZ40cTOif1xYA== X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2644a06a-c446-4f71-669e-08d7ab502065 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Feb 2020 22:01:34.1324 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: cAAgOQ2WTjlLtUBIXSDZ+WiNAxSE3vK8dWC0CeZ6PGnAvk6NjTp4PzpqmhM+F6VkpsPSzmFFwA2xPO/IDsTE6A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR2101MB1108 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The caller of XDP_SETUP_PROG has already incremented refcnt in __bpf_prog_get(), so drivers should only increment refcnt by num_queues - 1. To fix the issue, update netvsc_xdp_set() to add the correct number to refcnt. Hold a refcnt in netvsc_xdp_set()’s other caller, netvsc_attach(). And, do the same in netvsc_vf_setxdp(). Otherwise, every time when VF is removed and added from the host side, the refcnt will be decreased by one, which may cause page fault when unloading xdp program. Fixes: 351e1581395f ("hv_netvsc: Add XDP support") Signed-off-by: Haiyang Zhang --- drivers/net/hyperv/netvsc_bpf.c | 13 +++++++++++-- drivers/net/hyperv/netvsc_drv.c | 5 ++++- 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/net/hyperv/netvsc_bpf.c b/drivers/net/hyperv/netvsc_bpf.c index 20adfe5..b866110 100644 --- a/drivers/net/hyperv/netvsc_bpf.c +++ b/drivers/net/hyperv/netvsc_bpf.c @@ -120,7 +120,7 @@ int netvsc_xdp_set(struct net_device *dev, struct bpf_prog *prog, } if (prog) - bpf_prog_add(prog, nvdev->num_chn); + bpf_prog_add(prog, nvdev->num_chn - 1); for (i = 0; i < nvdev->num_chn; i++) rcu_assign_pointer(nvdev->chan_table[i].bpf_prog, prog); @@ -136,6 +136,7 @@ int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog) { struct netdev_bpf xdp; bpf_op_t ndo_bpf; + int ret; ASSERT_RTNL(); @@ -148,10 +149,18 @@ int netvsc_vf_setxdp(struct net_device *vf_netdev, struct bpf_prog *prog) memset(&xdp, 0, sizeof(xdp)); + if (prog) + bpf_prog_inc(prog); + xdp.command = XDP_SETUP_PROG; xdp.prog = prog; - return ndo_bpf(vf_netdev, &xdp); + ret = ndo_bpf(vf_netdev, &xdp); + + if (ret && prog) + bpf_prog_put(prog); + + return ret; } static u32 netvsc_xdp_query(struct netvsc_device *nvdev) diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 8fc71bd..65e12cb 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1059,9 +1059,12 @@ static int netvsc_attach(struct net_device *ndev, prog = dev_info->bprog; if (prog) { + bpf_prog_inc(prog); ret = netvsc_xdp_set(ndev, prog, NULL, nvdev); - if (ret) + if (ret) { + bpf_prog_put(prog); goto err1; + } } /* In any case device is now ready */ -- 1.8.3.1