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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 5D908C433DF for ; Mon, 12 Oct 2020 16:46:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E5C12076D for ; Mon, 12 Oct 2020 16:46:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="r6nJb6mV"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="fAr5FcJK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403868AbgJLQp5 (ORCPT ); Mon, 12 Oct 2020 12:45:57 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:46226 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390541AbgJLQp5 (ORCPT ); Mon, 12 Oct 2020 12:45:57 -0400 Date: Mon, 12 Oct 2020 18:45:53 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1602521155; 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: in-reply-to:in-reply-to:references:references; bh=Mw0frYjEmcHy+lH8fPEzgAzJHGlzJuO9p7Ascemyq/w=; b=r6nJb6mVGzNtSCCau9CHqK1EcFwlaoiWjGI6MoHFQV8nBsOIngm9C7rLQa/QzksrZj0Ud9 GLYv/4eeytJQK0gCpM3mSwmuxtpjTFKnu9Kkmk1fbByJH98yPPR49HenmrHltl7yVk4yvr lYrOHTWUo2aKxrkPIJe4zCmT6XAelfayfNvLEmV0k6S1MRhVODVn1wNeIJs7NSHTTXfoql 4Req1DjUan3zts+TStoGUC9p9RW2USsuL3ZPZ3CYrHVk18uwkr0wWuwUv1b/UVMdxjI1be 0OWt3Lbghjo4IT4PH+wsD7Vmydkzqkkg0KURJseOxWPqBml5agG0ZiWHyJWmjg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1602521155; 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: in-reply-to:in-reply-to:references:references; bh=Mw0frYjEmcHy+lH8fPEzgAzJHGlzJuO9p7Ascemyq/w=; b=fAr5FcJKsAqePv/01EfutuKixjyghotjPEhnnb7UEv8ifeRDe9FqypZ5iz9TAWtiZu+irM 1MLGREPg1O0mkjCQ== From: Sebastian Andrzej Siewior To: Mike Galbraith Cc: tglx@linutronix.de, linux-rt-users@vger.kernel.org, lkml Subject: Re: [RT] 5.9-rt14 softirq_ctrl.lock vs listening_hash[i].lock lockdep splat Message-ID: <20201012164553.kkk7aaeyb3y4wvyh@linutronix.de> References: <12d6f9879a97cd56c09fb53dee343cbb14f7f1f7.camel@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <12d6f9879a97cd56c09fb53dee343cbb14f7f1f7.camel@gmx.de> Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2020-10-10 06:31:57 [+0200], Mike Galbraith wrote: so this then. Do you have more of these? ----------->8-------------------- Subject: [PATCH] tcp: Remove superfluous BH-disable around listening_hash Commit 9652dc2eb9e40 ("tcp: relax listening_hash operations") removed the need to disable bottom half while acquiring listening_hash.lock. There are still two callers left which disable bottom half before the lock is acquired. Drop local_bh_disable() around __inet_hash() which acquires listening_hash->lock, invoke inet_ehash_nolisten() with disabled BH. inet_unhash() conditionally acquires listening_hash->lock. Signed-off-by: Sebastian Andrzej Siewior --- net/ipv4/inet_hashtables.c | 19 ++++++++++++------- net/ipv6/inet6_hashtables.c | 5 +---- 2 files changed, 13 insertions(+), 11 deletions(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 239e54474b653..fcb105cbb5465 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -585,7 +585,9 @@ int __inet_hash(struct sock *sk, struct sock *osk) int err = 0; if (sk->sk_state != TCP_LISTEN) { + local_bh_disable(); inet_ehash_nolisten(sk, osk); + local_bh_enable(); return 0; } WARN_ON(!sk_unhashed(sk)); @@ -617,11 +619,8 @@ int inet_hash(struct sock *sk) { int err = 0; - if (sk->sk_state != TCP_CLOSE) { - local_bh_disable(); + if (sk->sk_state != TCP_CLOSE) err = __inet_hash(sk, NULL); - local_bh_enable(); - } return err; } @@ -632,17 +631,20 @@ void inet_unhash(struct sock *sk) struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; struct inet_listen_hashbucket *ilb = NULL; spinlock_t *lock; + bool state_listen; if (sk_unhashed(sk)) return; if (sk->sk_state == TCP_LISTEN) { + state_listen = true; ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; - lock = &ilb->lock; + spin_lock(&ilb->lock); } else { + state_listen = false; lock = inet_ehash_lockp(hashinfo, sk->sk_hash); + spin_lock_bh(lock); } - spin_lock_bh(lock); if (sk_unhashed(sk)) goto unlock; @@ -655,7 +657,10 @@ void inet_unhash(struct sock *sk) __sk_nulls_del_node_init_rcu(sk); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); unlock: - spin_unlock_bh(lock); + if (state_listen) + spin_unlock(&ilb->lock); + else + spin_unlock_bh(lock); } EXPORT_SYMBOL_GPL(inet_unhash); diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 2d3add9e61162..50fd17cbf3ec7 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -335,11 +335,8 @@ int inet6_hash(struct sock *sk) { int err = 0; - if (sk->sk_state != TCP_CLOSE) { - local_bh_disable(); + if (sk->sk_state != TCP_CLOSE) err = __inet_hash(sk, NULL); - local_bh_enable(); - } return err; } -- 2.28.0