From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92D128BE0 for ; Tue, 28 Mar 2023 15:02:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 147F2C433EF; Tue, 28 Mar 2023 15:02:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680015760; bh=nnS8ynulsXOIo7/oz6jzSHL85+Xh6cvIqdqHlkubFLU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gYVMHaJorRwjhxB6JB3Rx3kft0pZfOVT3zGnaDEyIPQ4XyS/TREwUyl37Krj5LFxs dnRymGJsXSq2/7YTbyGrWt87zk6ifLKdE0ALb3ybesJzJA+8UjOBv5pN9MnAckW3nt ramyLYS2qXHwV0Dfj6wtbbxSw1Cw2zYksCBf5FtU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jamal Hadi Salim , Davide Caratti , Marcelo Ricardo Leitner , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 148/224] net/sched: act_mirred: better wording on protection against excessive stack growth Date: Tue, 28 Mar 2023 16:42:24 +0200 Message-Id: <20230328142623.531394338@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230328142617.205414124@linuxfoundation.org> References: <20230328142617.205414124@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Davide Caratti [ Upstream commit 78dcdffe0418ac8f3f057f26fe71ccf4d8ed851f ] with commit e2ca070f89ec ("net: sched: protect against stack overflow in TC act_mirred"), act_mirred protected itself against excessive stack growth using per_cpu counter of nested calls to tcf_mirred_act(), and capping it to MIRRED_RECURSION_LIMIT. However, such protection does not detect recursion/loops in case the packet is enqueued to the backlog (for example, when the mirred target device has RPS or skb timestamping enabled). Change the wording from "recursion" to "nesting" to make it more clear to readers. CC: Jamal Hadi Salim Signed-off-by: Davide Caratti Reviewed-by: Marcelo Ricardo Leitner Acked-by: Jamal Hadi Salim Signed-off-by: Paolo Abeni Stable-dep-of: ca22da2fbd69 ("act_mirred: use the backlog for nested calls to mirred ingress") Signed-off-by: Sasha Levin --- net/sched/act_mirred.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index b8ad6ae282c02..ded6ee054be14 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -28,8 +28,8 @@ static LIST_HEAD(mirred_list); static DEFINE_SPINLOCK(mirred_list_lock); -#define MIRRED_RECURSION_LIMIT 4 -static DEFINE_PER_CPU(unsigned int, mirred_rec_level); +#define MIRRED_NEST_LIMIT 4 +static DEFINE_PER_CPU(unsigned int, mirred_nest_level); static bool tcf_mirred_is_act_redirect(int action) { @@ -224,7 +224,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, struct sk_buff *skb2 = skb; bool m_mac_header_xmit; struct net_device *dev; - unsigned int rec_level; + unsigned int nest_level; int retval, err = 0; bool use_reinsert; bool want_ingress; @@ -235,11 +235,11 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, int mac_len; bool at_nh; - rec_level = __this_cpu_inc_return(mirred_rec_level); - if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) { + nest_level = __this_cpu_inc_return(mirred_nest_level); + if (unlikely(nest_level > MIRRED_NEST_LIMIT)) { net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n", netdev_name(skb->dev)); - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return TC_ACT_SHOT; } @@ -308,7 +308,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, err = tcf_mirred_forward(want_ingress, skb); if (err) tcf_action_inc_overlimit_qstats(&m->common); - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return TC_ACT_CONSUMED; } } @@ -320,7 +320,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, if (tcf_mirred_is_act_redirect(m_eaction)) retval = TC_ACT_SHOT; } - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return retval; } -- 2.39.2