From patchwork Wed Dec 9 11:18:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= X-Patchwork-Id: 11961117 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A52D6C1B0D8 for ; Wed, 9 Dec 2020 11:21:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AED42343F for ; Wed, 9 Dec 2020 11:21:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730662AbgLILVR (ORCPT ); Wed, 9 Dec 2020 06:21:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:60333 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730317AbgLILUO (ORCPT ); Wed, 9 Dec 2020 06:20:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607512726; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ICznRmJm5dVUGmr9DiortfE3N0uQK/Rp9N47GmwoLqA=; b=M58TPkBS21hyA83y5kVHePibD8+ofrJUtA7kmLQUMaPvosvG4r1w8nqWmbCWl99glXFqlv 40mgHk05FfXHDPThBfX46OninFJigSF39M/lT2+jNj3aZom0W1Icye7M6y5qCjBvsGr/K4 xNuJv+DoPyyQaL3NpEvbt+fGw/if/S0= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-236-uqO4oJVyPKWqEnoNyPompw-1; Wed, 09 Dec 2020 06:18:43 -0500 X-MC-Unique: uqO4oJVyPKWqEnoNyPompw-1 Received: by mail-wm1-f71.google.com with SMTP id l5so255922wmi.4 for ; Wed, 09 Dec 2020 03:18:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=ICznRmJm5dVUGmr9DiortfE3N0uQK/Rp9N47GmwoLqA=; b=fzIOowPu7+VaAbfRFAs8entA8a8hfXJ5u8oRKFnCmWFERUEiM+YYmSLhq/eKkkRBf8 f9nWmJXef0QwduuU9Iiyvu1M1KAr2e28X80m+KDucphdNT5EtROuxexyiKujqwBI5ozI OmHRL2ZYEZyDWfeoLqiQG/pR1ma3RlguPtMBQzvX0+4gopbqw2troMaPZGVqZL5HkRiz VnZSNXwW/EWOJbNx4d1BHvAiZFudt34XLaQotZhg3qho6q6TCTI6iK42u7FX/ce/KZZO 7V8xglOQ6c+swKFGcp/9Wi0gXvJrWr7j3kzhbdtvBfHHDcuhzHid3Gh3rcRbXVHKwKpN 6MZQ== X-Gm-Message-State: AOAM533EfEfP5DzCMuv7Png+Z7EI4N0nvjVwS4a3OKHvIvmC6zNEh/T2 YIZscN/Chm7ofXJ6r7VvVZooeKYUncz9cKQl0lDtGfBoDEK3jIzX5hKLI0sLK7f1BA65+IHz2f1 DXBKIrMOmMh1l X-Received: by 2002:a1c:46c5:: with SMTP id t188mr2244410wma.3.1607512721545; Wed, 09 Dec 2020 03:18:41 -0800 (PST) X-Google-Smtp-Source: ABdhPJzsjN8rtB0x2Qe/UzkwKnGOYovEgAud1os2UtZyiOyp7h6thRolybgYwGlOHZ8V21PuGhd/pg== X-Received: by 2002:a1c:46c5:: with SMTP id t188mr2244346wma.3.1607512720752; Wed, 09 Dec 2020 03:18:40 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([2a0c:4d80:42:443::2]) by smtp.gmail.com with ESMTPSA id g192sm2711608wme.48.2020.12.09.03.18.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Dec 2020 03:18:39 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 2D136180004; Wed, 9 Dec 2020 12:18:39 +0100 (CET) Subject: [PATCH bpf v3 1/7] xdp: remove the xdp_attachment_flags_ok() callback From: =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= To: Jakub Kicinski Cc: "David S. Miller" , Daniel Borkmann , Alexei Starovoitov , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Jesper Dangaard Brouer , "Michael S. Tsirkin" , Romain Perier , Allen Pais , Grygorii Strashko , Simon Horman , "Gustavo A. R. Silva" , Lorenzo Bianconi , Wei Yongjun , Jiri Benc , oss-drivers@netronome.com, linux-omap@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org Date: Wed, 09 Dec 2020 12:18:39 +0100 Message-ID: <160751271909.104774.6106391152070643541.stgit@toke.dk> In-Reply-To: <160751271801.104774.5575431902172553440.stgit@toke.dk> References: <160751271801.104774.5575431902172553440.stgit@toke.dk> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Toke Høiland-Jørgensen Since commit 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device"), the XDP program attachment info is now maintained in the core code. This interacts badly with the xdp_attachment_flags_ok() check that prevents unloading an XDP program with different load flags than it was loaded with. In practice, two kinds of failures are seen: - An XDP program loaded without specifying a mode (and which then ends up in driver mode) cannot be unloaded if the program mode is specified on unload. - The dev_xdp_uninstall() hook always calls the driver callback with the mode set to the type of the program but an empty flags argument, which means the flags_ok() check prevents the program from being removed, leading to bpf prog reference leaks. The original reason this check was added was to avoid ambiguity when multiple programs were loaded. With the way the checks are done in the core now, this is quite simple to enforce in the core code, so let's add a check there and get rid of the xdp_attachment_flags_ok() callback entirely. Fixes: 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device") Signed-off-by: Toke Høiland-Jørgensen --- .../net/ethernet/netronome/nfp/nfp_net_common.c | 6 ----- drivers/net/ethernet/ti/cpsw_priv.c | 3 --- drivers/net/netdevsim/bpf.c | 3 --- include/net/xdp.h | 2 -- net/core/dev.c | 22 ++++++++++++++++++-- net/core/xdp.c | 12 ----------- 6 files changed, 20 insertions(+), 28 deletions(-) diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c index b150da43adb2..437226866ce8 100644 --- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c @@ -3562,9 +3562,6 @@ static int nfp_net_xdp_setup_drv(struct nfp_net *nn, struct netdev_bpf *bpf) struct nfp_net_dp *dp; int err; - if (!xdp_attachment_flags_ok(&nn->xdp, bpf)) - return -EBUSY; - if (!prog == !nn->dp.xdp_prog) { WRITE_ONCE(nn->dp.xdp_prog, prog); xdp_attachment_setup(&nn->xdp, bpf); @@ -3593,9 +3590,6 @@ static int nfp_net_xdp_setup_hw(struct nfp_net *nn, struct netdev_bpf *bpf) { int err; - if (!xdp_attachment_flags_ok(&nn->xdp_hw, bpf)) - return -EBUSY; - err = nfp_app_xdp_offload(nn->app, nn, bpf->prog, bpf->extack); if (err) return err; diff --git a/drivers/net/ethernet/ti/cpsw_priv.c b/drivers/net/ethernet/ti/cpsw_priv.c index 31c5e36ff706..424e644724e4 100644 --- a/drivers/net/ethernet/ti/cpsw_priv.c +++ b/drivers/net/ethernet/ti/cpsw_priv.c @@ -1265,9 +1265,6 @@ static int cpsw_xdp_prog_setup(struct cpsw_priv *priv, struct netdev_bpf *bpf) if (!priv->xdpi.prog && !prog) return 0; - if (!xdp_attachment_flags_ok(&priv->xdpi, bpf)) - return -EBUSY; - WRITE_ONCE(priv->xdp_prog, prog); xdp_attachment_setup(&priv->xdpi, bpf); diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c index 2e90512f3bbe..85546664bdd5 100644 --- a/drivers/net/netdevsim/bpf.c +++ b/drivers/net/netdevsim/bpf.c @@ -190,9 +190,6 @@ nsim_xdp_set_prog(struct netdevsim *ns, struct netdev_bpf *bpf, { int err; - if (!xdp_attachment_flags_ok(xdp, bpf)) - return -EBUSY; - if (bpf->command == XDP_SETUP_PROG && !ns->bpf_xdpdrv_accept) { NSIM_EA(bpf->extack, "driver XDP disabled in DebugFS"); return -EOPNOTSUPP; diff --git a/include/net/xdp.h b/include/net/xdp.h index 3814fb631d52..9dab2bc6f187 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -240,8 +240,6 @@ struct xdp_attachment_info { }; struct netdev_bpf; -bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, - struct netdev_bpf *bpf); void xdp_attachment_setup(struct xdp_attachment_info *info, struct netdev_bpf *bpf); diff --git a/net/core/dev.c b/net/core/dev.c index 8588ade790cb..38412e70f761 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8917,6 +8917,17 @@ static struct bpf_prog *dev_xdp_prog(struct net_device *dev, return dev->xdp_state[mode].prog; } +static u8 dev_xdp_prog_count(struct net_device *dev) +{ + u8 count = 0; + int i; + + for (i = 0; i < __MAX_XDP_MODE; i++) + if (dev->xdp_state[i].prog || dev->xdp_state[i].link) + count++; + return count; +} + u32 dev_xdp_prog_id(struct net_device *dev, enum bpf_xdp_mode mode) { struct bpf_prog *prog = dev_xdp_prog(dev, mode); @@ -9007,6 +9018,7 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack struct bpf_xdp_link *link, struct bpf_prog *new_prog, struct bpf_prog *old_prog, u32 flags) { + unsigned int num_modes = hweight32(flags & XDP_FLAGS_MODES); struct bpf_prog *cur_prog; enum bpf_xdp_mode mode; bpf_op_t bpf_op; @@ -9022,11 +9034,17 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack NL_SET_ERR_MSG(extack, "Invalid XDP flags for BPF link attachment"); return -EINVAL; } - /* just one XDP mode bit should be set, zero defaults to SKB mode */ - if (hweight32(flags & XDP_FLAGS_MODES) > 1) { + /* just one XDP mode bit should be set, zero defaults to drv/skb mode */ + if (num_modes > 1) { NL_SET_ERR_MSG(extack, "Only one XDP mode flag can be set"); return -EINVAL; } + /* avoid ambiguity if offload + drv/skb mode progs are both loaded */ + if (!num_modes && dev_xdp_prog_count(dev) > 1) { + NL_SET_ERR_MSG(extack, + "More than one program loaded, unset mode is ambiguous"); + return -EINVAL; + } /* old_prog != NULL implies XDP_FLAGS_REPLACE is set */ if (old_prog && !(flags & XDP_FLAGS_REPLACE)) { NL_SET_ERR_MSG(extack, "XDP_FLAGS_REPLACE is not specified"); diff --git a/net/core/xdp.c b/net/core/xdp.c index 491ad569a79c..d900cebc0acd 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -403,18 +403,6 @@ void __xdp_release_frame(void *data, struct xdp_mem_info *mem) } EXPORT_SYMBOL_GPL(__xdp_release_frame); -bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, - struct netdev_bpf *bpf) -{ - if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) { - NL_SET_ERR_MSG(bpf->extack, - "program loaded with different flags"); - return false; - } - return true; -} -EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok); - void xdp_attachment_setup(struct xdp_attachment_info *info, struct netdev_bpf *bpf) {