From patchwork Thu Apr 3 08:39:56 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Iurman X-Patchwork-Id: 14036702 X-Patchwork-Delegate: kuba@kernel.org Received: from serv108.segi.ulg.ac.be (serv108.segi.ulg.ac.be [139.165.32.111]) (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 C35D81F03CB; Thu, 3 Apr 2025 08:40:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=139.165.32.111 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743669637; cv=none; b=QY4j5b+0dTqbugrhxbokB/AnGYobhKbjG1+joXwGP7PCv7FUPYoxud2jl3pXMKy2JnELyOcaOfyV+SjOzOQ69oauRqJ0ejcXvX6ceScajXS437oOpv5+LxTtVR1fnZ3MYX/viqp+mL+2KalUyG0DbBUR3ffMEPZu6rMZZnMOT+U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743669637; c=relaxed/simple; bh=adNmKijgwJ0/HuyYribCZ1SflALgeVpdt9ZDAd8R8f8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gBT3na7UD4mdsnp056Vydde7dL/x3JfyhLGKcJL/ao5PshnwJNrWZReT2AgOtI/DMh+NsFQKuA7Wf16x848uBflSDlH20eBtWBzbnNQL1l+UO+vAcfVFBXo/QaggKaqinpSW+mVUgeiCouTAgwfvfIaAZu8CwUF9HkNOMe9POGU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uliege.be; spf=pass smtp.mailfrom=uliege.be; dkim=pass (2048-bit key) header.d=uliege.be header.i=@uliege.be header.b=qC4mrEeX; arc=none smtp.client-ip=139.165.32.111 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uliege.be Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=uliege.be Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=uliege.be header.i=@uliege.be header.b="qC4mrEeX" Received: from ubuntu.home (220.24-245-81.adsl-dyn.isp.belgacom.be [81.245.24.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by serv108.segi.ulg.ac.be (Postfix) with ESMTPSA id D00A9200A728; Thu, 3 Apr 2025 10:40:25 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 serv108.segi.ulg.ac.be D00A9200A728 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uliege.be; s=ulg20190529; t=1743669626; bh=94DJ7KtPQKubwfSja/wln0B8MjCkiuH0R9N/UpDkdu8=; h=From:To:Cc:Subject:Date:From; b=qC4mrEeXIlQbcEHZIvGjHX2tGfByiQQd7iOyDqXJmls0X1oYFndmOj9uE36Y3jQOH 3jNjR0GCM2LZAqEO99ZohOCxP/JqBc3d/38sSAMgZIB5BiDwjiRAPmyxIJjjkJtB/x 1SKJyTUjxMyy7bcBaRuAj0/dUVkwt3myWYU5qzZRaK/0TuBwI2etY6HXOvf1b7vqif 2zWm8FDfZrCY81vqhnGqJydUkPQsijjqvxUOEXUcqn7pKFuVLagE69wfNnUrM58tI7 3cZ/R/N8UiaMevmSYCwN6iVIGrDB5iNYduprAwatAb5bxyuqDlW7UkTM+C+mP2XT3J WtvpqvjKa3+pA== From: Justin Iurman To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, kuniyu@amazon.com, justin.iurman@uliege.be, Alexei Starovoitov , bpf , Stanislav Fomichev Subject: [PATCH net] net: lwtunnel: disable preemption when required Date: Thu, 3 Apr 2025 10:39:56 +0200 Message-Id: <20250403083956.13946-1-justin.iurman@uliege.be> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org In lwtunnel_{input|output|xmit}(), dev_xmit_recursion() may be called in preemptible scope for PREEMPT kernels. This patch disables preemption before calling dev_xmit_recursion(). Preemption is re-enabled only at the end, since we must ensure the same CPU is used for both dev_xmit_recursion_inc() and dev_xmit_recursion_dec() (and any other recursion levels in some cases) in order to maintain valid per-cpu counters. Reported-by: Alexei Starovoitov Closes: https://lore.kernel.org/netdev/CAADnVQJFWn3dBFJtY+ci6oN1pDFL=TzCmNbRgey7MdYxt_AP2g@mail.gmail.com/ Fixes: 986ffb3a57c5 ("net: lwtunnel: fix recursion loops") Signed-off-by: Justin Iurman --- Cc: bpf Cc: Alexei Starovoitov Cc: Stanislav Fomichev --- net/core/lwtunnel.c | 47 ++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c index e39a459540ec..a9ad068e5707 100644 --- a/net/core/lwtunnel.c +++ b/net/core/lwtunnel.c @@ -333,6 +333,8 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) struct dst_entry *dst; int ret; + preempt_disable(); + if (dev_xmit_recursion()) { net_crit_ratelimited("%s(): recursion limit reached on datapath\n", __func__); @@ -345,11 +347,13 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) ret = -EINVAL; goto drop; } - lwtstate = dst->lwtstate; + lwtstate = dst->lwtstate; if (lwtstate->type == LWTUNNEL_ENCAP_NONE || - lwtstate->type > LWTUNNEL_ENCAP_MAX) - return 0; + lwtstate->type > LWTUNNEL_ENCAP_MAX) { + ret = 0; + goto out; + } ret = -EOPNOTSUPP; rcu_read_lock(); @@ -364,11 +368,11 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) if (ret == -EOPNOTSUPP) goto drop; - return ret; - + goto out; drop: kfree_skb(skb); - +out: + preempt_enable(); return ret; } EXPORT_SYMBOL_GPL(lwtunnel_output); @@ -380,6 +384,8 @@ int lwtunnel_xmit(struct sk_buff *skb) struct dst_entry *dst; int ret; + preempt_disable(); + if (dev_xmit_recursion()) { net_crit_ratelimited("%s(): recursion limit reached on datapath\n", __func__); @@ -394,10 +400,11 @@ int lwtunnel_xmit(struct sk_buff *skb) } lwtstate = dst->lwtstate; - if (lwtstate->type == LWTUNNEL_ENCAP_NONE || - lwtstate->type > LWTUNNEL_ENCAP_MAX) - return 0; + lwtstate->type > LWTUNNEL_ENCAP_MAX) { + ret = 0; + goto out; + } ret = -EOPNOTSUPP; rcu_read_lock(); @@ -412,11 +419,11 @@ int lwtunnel_xmit(struct sk_buff *skb) if (ret == -EOPNOTSUPP) goto drop; - return ret; - + goto out; drop: kfree_skb(skb); - +out: + preempt_enable(); return ret; } EXPORT_SYMBOL_GPL(lwtunnel_xmit); @@ -428,6 +435,8 @@ int lwtunnel_input(struct sk_buff *skb) struct dst_entry *dst; int ret; + preempt_disable(); + if (dev_xmit_recursion()) { net_crit_ratelimited("%s(): recursion limit reached on datapath\n", __func__); @@ -440,11 +449,13 @@ int lwtunnel_input(struct sk_buff *skb) ret = -EINVAL; goto drop; } - lwtstate = dst->lwtstate; + lwtstate = dst->lwtstate; if (lwtstate->type == LWTUNNEL_ENCAP_NONE || - lwtstate->type > LWTUNNEL_ENCAP_MAX) - return 0; + lwtstate->type > LWTUNNEL_ENCAP_MAX) { + ret = 0; + goto out; + } ret = -EOPNOTSUPP; rcu_read_lock(); @@ -459,11 +470,11 @@ int lwtunnel_input(struct sk_buff *skb) if (ret == -EOPNOTSUPP) goto drop; - return ret; - + goto out; drop: kfree_skb(skb); - +out: + preempt_enable(); return ret; } EXPORT_SYMBOL_GPL(lwtunnel_input);