From patchwork Tue Apr 15 17:32:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Iurman X-Patchwork-Id: 14052503 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 A304918FDD2; Tue, 15 Apr 2025 17:33:03 +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=1744738386; cv=none; b=NVPsp7fwsyksI7/CtOx3mLGaFixIQOI6yLI3/2buT7EG1Wp63OFmRWv0RrIYW85MItM/lP0UuglrpE2cnfhYXXgzDeHjEykCYsJeYq6dBFHXD19nTj9iWesjP6QW6Wwb823PWWJg5RvlfKokVDQOAVSk34QkPcIDJ41wAOMLxco= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744738386; c=relaxed/simple; bh=1szZC1eehH1SsFARH9SlXFiTiHnWWh4RUAwSHezPxUM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=S3SVlj0woieWkRLnXKP8iRPzr1AASmXVIvARXRHcA3rNngDanxHq6A2XX3uj6qdfCUb7VYt6gWYzRqGet5BtcL3xWoQgF5nbd1+f3htt/py//DuqCwY4IcO621rCYqtAKFUQ5ZYFoac2kLQMFqgVKenamWNieVRi7pnmmrVJHN8= 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=IowmYnlh; 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="IowmYnlh" Received: from localhost.localdomain (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 97E1E200DB80; Tue, 15 Apr 2025 19:33:01 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 serv108.segi.ulg.ac.be 97E1E200DB80 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uliege.be; s=ulg20190529; t=1744738381; bh=IbQmDsgxJdY2+2UAwOgv5kT7783Rv22sijWahhN2N3o=; h=From:To:Cc:Subject:Date:From; b=IowmYnlhiqIVEWxVua8MbV112+Hhw2Hwyj95pby/42Wptq0TC1neWPoOd6cf7Hg39 KvZOoQyet53aaPgjHl5Xc/UdclY8MmkgW2EHlqW5eRwvlSes5zxXoLKm/iCFgPxwDc C//LcbJeDnJu37n4XICMfjuLG5zRNKeEcj32H+6PlFomq6cPUpc9GwU7qUhGtPmRfo N271lnoSGhLu3XqKkt75ufsaNtQqUv+kGvUAp7P9aWnJHHCRxCRVE76gCMj5YNBUje 30goexQoOzF2tASe71/ExJxGQdWqW8ahCRf2bDnfD/wyEseIjT8XZSKwb3Ujk6JZer P4cyoBjeFEwcw== 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 , Eduard Zingerman , bpf , Stanislav Fomichev , Sebastian Sewior , Andrea Mayer , Stefano Salsano , Paolo Lungaroni Subject: [PATCH net v2] net: lwtunnel: disable BHs when required Date: Tue, 15 Apr 2025 19:32:39 +0200 Message-Id: <20250415173239.39781-1-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 v2: - replaced preempt_{disable|enable}() by local_bh_{disable|enable}() - not in lwtunnel_input() since BHs are already disabled on that path v1: - https://lore.kernel.org/netdev/20250403083956.13946-1-justin.iurman@uliege.be/ In lwtunnel_{output|xmit}(), dev_xmit_recursion() may be called in preemptible scope for PREEMPT kernels. This patch disables BHs before calling dev_xmit_recursion(). BHs are 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/ Reported-by: Eduard Zingerman Closes: https://lore.kernel.org/netdev/m2h62qwf34.fsf@gmail.com/ Fixes: 986ffb3a57c5 ("net: lwtunnel: fix recursion loops") Signed-off-by: Justin Iurman --- Cc: bpf Cc: Alexei Starovoitov Cc: Stanislav Fomichev Cc: Sebastian Sewior Cc: Andrea Mayer Cc: Stefano Salsano Cc: Paolo Lungaroni --- net/core/lwtunnel.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c index e39a459540ec..cc1b78616a94 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; + local_bh_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: + local_bh_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; + local_bh_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: + local_bh_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; + DEBUG_NET_WARN_ON_ONCE(!in_softirq()); + if (dev_xmit_recursion()) { net_crit_ratelimited("%s(): recursion limit reached on datapath\n", __func__); @@ -440,8 +449,8 @@ 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; @@ -460,10 +469,8 @@ int lwtunnel_input(struct sk_buff *skb) goto drop; return ret; - drop: kfree_skb(skb); - return ret; } EXPORT_SYMBOL_GPL(lwtunnel_input);