From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 3FDA5C433E0 for ; Mon, 1 Mar 2021 16:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4FF964D90 for ; Mon, 1 Mar 2021 16:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237539AbhCAQFu (ORCPT ); Mon, 1 Mar 2021 11:05:50 -0500 Received: from forward5-smtp.messagingengine.com ([66.111.4.239]:37431 "EHLO forward5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237488AbhCAQE1 (ORCPT ); Mon, 1 Mar 2021 11:04:27 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailforward.nyi.internal (Postfix) with ESMTP id 5C30519428FE; Mon, 1 Mar 2021 11:02:57 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Mon, 01 Mar 2021 11:02:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=/Xm+tt Db3WTJOcM42M/XSf0fu2wyJ9HBIn4dmaut1ZE=; b=n2l5LCZjmEj8kVBi/RRVPR vNSlqVBc1M1ERSJzYKjDHY6ZkMTs+qcfdS7L95Xt73ivCeqc7DmzAlSAwR8tEITd ggyYaHP0x15SDHdaKRuqDEcLjNzxEs0ZqB48UBkq/1LlS3WINN5mZeiUDbH2izC5 DsXmVtzXh7zY7LqRb+wGiM3JGnXK2m6w5vkOdgK8IR2YTLtmq4QZmEMbNpZ1E4ea A0FlF4tL4IE+JztLZdtHXO4LHJVuqRIk7PwXCH8MNHFySfXvrweJV2SKElrkiAFI 6YPlVZemS+HI3EYzRJCnbB4J6Cp9AJx7cDUQd7/hME1JpR05jIxxkwewsxsvkU2A == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrleekgdekvdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucggtffrrghtthgvrhhnpeelleelvdegfeelledtteegudegfffghfduffduudekge efleegieegkeejhfelveenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeek fedrkeeirdejgedrieegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrg hilhhfrhhomhepghhrvghgsehkrhhorghhrdgtohhm X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id 8BD6E240054; Mon, 1 Mar 2021 11:02:56 -0500 (EST) Subject: FAILED: patch "[PATCH] net_sched: fix RTNL deadlock again caused by request_module()" failed to apply to 5.4-stable tree To: cong.wang@bytedance.com, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org Cc: From: Date: Mon, 01 Mar 2021 17:02:54 +0100 Message-ID: <161461457416034@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From d349f997686887906b1183b5be96933c5452362a Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Sat, 16 Jan 2021 16:56:57 -0800 Subject: [PATCH] net_sched: fix RTNL deadlock again caused by request_module() tcf_action_init_1() loads tc action modules automatically with request_module() after parsing the tc action names, and it drops RTNL lock and re-holds it before and after request_module(). This causes a lot of troubles, as discovered by syzbot, because we can be in the middle of batch initializations when we create an array of tc actions. One of the problem is deadlock: CPU 0 CPU 1 rtnl_lock(); for (...) { tcf_action_init_1(); -> rtnl_unlock(); -> request_module(); rtnl_lock(); for (...) { tcf_action_init_1(); -> tcf_idr_check_alloc(); // Insert one action into idr, // but it is not committed until // tcf_idr_insert_many(), then drop // the RTNL lock in the _next_ // iteration -> rtnl_unlock(); -> rtnl_lock(); -> a_o->init(); -> tcf_idr_check_alloc(); // Now waiting for the same index // to be committed -> request_module(); -> rtnl_lock() // Now waiting for RTNL lock } rtnl_unlock(); } rtnl_unlock(); This is not easy to solve, we can move the request_module() before this loop and pre-load all the modules we need for this netlink message and then do the rest initializations. So the loop breaks down to two now: for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) { struct tc_action_ops *a_o; a_o = tc_action_load_ops(name, tb[i]...); ops[i - 1] = a_o; } for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) { act = tcf_action_init_1(ops[i - 1]...); } Although this looks serious, it only has been reported by syzbot, so it seems hard to trigger this by humans. And given the size of this patch, I'd suggest to make it to net-next and not to backport to stable. This patch has been tested by syzbot and tested with tdc.py by me. Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together") Reported-and-tested-by: syzbot+82752bc5331601cf4899@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+b3b63b6bff456bd95294@syzkaller.appspotmail.com Reported-by: syzbot+ba67b12b1ca729912834@syzkaller.appspotmail.com Cc: Jiri Pirko Signed-off-by: Cong Wang Tested-by: Jamal Hadi Salim Acked-by: Jamal Hadi Salim Link: https://lore.kernel.org/r/20210117005657.14810-1-xiyou.wangcong@gmail.com Signed-off-by: Jakub Kicinski diff --git a/include/net/act_api.h b/include/net/act_api.h index 55dab604861f..761c0e331915 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -186,10 +186,13 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla, struct nlattr *est, char *name, int ovr, int bind, struct tc_action *actions[], size_t *attr_size, bool rtnl_held, struct netlink_ext_ack *extack); +struct tc_action_ops *tc_action_load_ops(char *name, struct nlattr *nla, + bool rtnl_held, + struct netlink_ext_ack *extack); struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, struct nlattr *nla, struct nlattr *est, char *name, int ovr, int bind, - bool rtnl_held, + struct tc_action_ops *ops, bool rtnl_held, struct netlink_ext_ack *extack); int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[], int bind, int ref, bool terse); diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 2e85b636b27b..4dd235ce9a07 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -928,19 +928,13 @@ static void tcf_idr_insert_many(struct tc_action *actions[]) } } -struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, - struct nlattr *nla, struct nlattr *est, - char *name, int ovr, int bind, - bool rtnl_held, - struct netlink_ext_ack *extack) +struct tc_action_ops *tc_action_load_ops(char *name, struct nlattr *nla, + bool rtnl_held, + struct netlink_ext_ack *extack) { - struct nla_bitfield32 flags = { 0, 0 }; - u8 hw_stats = TCA_ACT_HW_STATS_ANY; - struct tc_action *a; + struct nlattr *tb[TCA_ACT_MAX + 1]; struct tc_action_ops *a_o; - struct tc_cookie *cookie = NULL; char act_name[IFNAMSIZ]; - struct nlattr *tb[TCA_ACT_MAX + 1]; struct nlattr *kind; int err; @@ -948,33 +942,21 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, err = nla_parse_nested_deprecated(tb, TCA_ACT_MAX, nla, tcf_action_policy, extack); if (err < 0) - goto err_out; + return ERR_PTR(err); err = -EINVAL; kind = tb[TCA_ACT_KIND]; if (!kind) { NL_SET_ERR_MSG(extack, "TC action kind must be specified"); - goto err_out; + return ERR_PTR(err); } if (nla_strscpy(act_name, kind, IFNAMSIZ) < 0) { NL_SET_ERR_MSG(extack, "TC action name too long"); - goto err_out; - } - if (tb[TCA_ACT_COOKIE]) { - cookie = nla_memdup_cookie(tb); - if (!cookie) { - NL_SET_ERR_MSG(extack, "No memory to generate TC cookie"); - err = -ENOMEM; - goto err_out; - } + return ERR_PTR(err); } - hw_stats = tcf_action_hw_stats_get(tb[TCA_ACT_HW_STATS]); - if (tb[TCA_ACT_FLAGS]) - flags = nla_get_bitfield32(tb[TCA_ACT_FLAGS]); } else { if (strlcpy(act_name, name, IFNAMSIZ) >= IFNAMSIZ) { NL_SET_ERR_MSG(extack, "TC action name too long"); - err = -EINVAL; - goto err_out; + return ERR_PTR(-EINVAL); } } @@ -996,24 +978,56 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, * indicate this using -EAGAIN. */ if (a_o != NULL) { - err = -EAGAIN; - goto err_mod; + module_put(a_o->owner); + return ERR_PTR(-EAGAIN); } #endif NL_SET_ERR_MSG(extack, "Failed to load TC action module"); - err = -ENOENT; - goto err_free; + return ERR_PTR(-ENOENT); } + return a_o; +} + +struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, + struct nlattr *nla, struct nlattr *est, + char *name, int ovr, int bind, + struct tc_action_ops *a_o, bool rtnl_held, + struct netlink_ext_ack *extack) +{ + struct nla_bitfield32 flags = { 0, 0 }; + u8 hw_stats = TCA_ACT_HW_STATS_ANY; + struct nlattr *tb[TCA_ACT_MAX + 1]; + struct tc_cookie *cookie = NULL; + struct tc_action *a; + int err; + /* backward compatibility for policer */ - if (name == NULL) + if (name == NULL) { + err = nla_parse_nested_deprecated(tb, TCA_ACT_MAX, nla, + tcf_action_policy, extack); + if (err < 0) + return ERR_PTR(err); + if (tb[TCA_ACT_COOKIE]) { + cookie = nla_memdup_cookie(tb); + if (!cookie) { + NL_SET_ERR_MSG(extack, "No memory to generate TC cookie"); + err = -ENOMEM; + goto err_out; + } + } + hw_stats = tcf_action_hw_stats_get(tb[TCA_ACT_HW_STATS]); + if (tb[TCA_ACT_FLAGS]) + flags = nla_get_bitfield32(tb[TCA_ACT_FLAGS]); + err = a_o->init(net, tb[TCA_ACT_OPTIONS], est, &a, ovr, bind, rtnl_held, tp, flags.value, extack); - else + } else { err = a_o->init(net, nla, est, &a, ovr, bind, rtnl_held, tp, flags.value, extack); + } if (err < 0) - goto err_mod; + goto err_out; if (!name && tb[TCA_ACT_COOKIE]) tcf_set_action_cookie(&a->act_cookie, cookie); @@ -1030,14 +1044,11 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, return a; -err_mod: - module_put(a_o->owner); -err_free: +err_out: if (cookie) { kfree(cookie->data); kfree(cookie); } -err_out: return ERR_PTR(err); } @@ -1048,6 +1059,7 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla, struct tc_action *actions[], size_t *attr_size, bool rtnl_held, struct netlink_ext_ack *extack) { + struct tc_action_ops *ops[TCA_ACT_MAX_PRIO] = {}; struct nlattr *tb[TCA_ACT_MAX_PRIO + 1]; struct tc_action *act; size_t sz = 0; @@ -1059,9 +1071,20 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla, if (err < 0) return err; + for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) { + struct tc_action_ops *a_o; + + a_o = tc_action_load_ops(name, tb[i], rtnl_held, extack); + if (IS_ERR(a_o)) { + err = PTR_ERR(a_o); + goto err_mod; + } + ops[i - 1] = a_o; + } + for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) { act = tcf_action_init_1(net, tp, tb[i], est, name, ovr, bind, - rtnl_held, extack); + ops[i - 1], rtnl_held, extack); if (IS_ERR(act)) { err = PTR_ERR(act); goto err; @@ -1081,6 +1104,11 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla, err: tcf_action_destroy(actions, bind); +err_mod: + for (i = 0; i < TCA_ACT_MAX_PRIO; i++) { + if (ops[i]) + module_put(ops[i]->owner); + } return err; } diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 37b77bd30974..a67c66a512a4 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3043,12 +3043,19 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, size_t attr_size = 0; if (exts->police && tb[exts->police]) { + struct tc_action_ops *a_o; + + a_o = tc_action_load_ops("police", tb[exts->police], rtnl_held, extack); + if (IS_ERR(a_o)) + return PTR_ERR(a_o); act = tcf_action_init_1(net, tp, tb[exts->police], rate_tlv, "police", ovr, - TCA_ACT_BIND, rtnl_held, + TCA_ACT_BIND, a_o, rtnl_held, extack); - if (IS_ERR(act)) + if (IS_ERR(act)) { + module_put(a_o->owner); return PTR_ERR(act); + } act->type = exts->type = TCA_OLD_COMPAT; exts->actions[0] = act;