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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C187C433FE for ; Fri, 18 Nov 2022 19:19:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242339AbiKRTTj (ORCPT ); Fri, 18 Nov 2022 14:19:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241828AbiKRTTa (ORCPT ); Fri, 18 Nov 2022 14:19:30 -0500 Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 475EB654CC for ; Fri, 18 Nov 2022 11:19:28 -0800 (PST) Received: by mail-qk1-x72c.google.com with SMTP id i9so4106536qki.10 for ; Fri, 18 Nov 2022 11:19:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=DPpwqLUbnT1bAnW/zW+E67t6MBL3eH6A9u0qDYvFcWw=; b=u/2XfL0tPG6GBJLPYyTHlLt/PrZI3yVn8VxWlCWjWq3ieouEHW2Ws/jpTVeMP+Mwlr LemZtoszK8Ff3Z2vtK/bRbwa/acoEfwUlIVs0ebNc4+08hlP6z5ChCPTCPBxPRmhQeQH /TOKyl7UElbeQMdAC+Clax4UCy9klC7bUs4ks= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=DPpwqLUbnT1bAnW/zW+E67t6MBL3eH6A9u0qDYvFcWw=; b=ekEU5a7kla6bXK9y9NAiVxCUTx+YBCP/j91ftBwqJobnWWInnNW3c49UV1LfLtjFXW oRhW4aq/dHNZoZ6TjOOibMZLseDauuGhjFTn1klMzk7l0azv0zDMZfRoT4NYBLgPnEbz 0YRJNAu93brMJG0g3BR7DKoAWoYIYZZkAjgdep7FmSr3kxwDEo41Q6Srug+Z0wqYKnFG gvgzInSgXrq/ttX7bY8hDVLl/9y8PVjIH6QgJgpcFNLQ65xgoCT78Np104zTsAYiKzSl Xn+MqU9Q+2zR4MfCR5ZfluRjcf2qYS7K/iGOyELx/AvvkbDmwoIQIyGtZoyrTMXmjAni 09EQ== X-Gm-Message-State: ANoB5pkvn7lLSFejTsXaNpz8RzEWLf8zRJ6+SoBfWbUHy5bpssrw137N n2v5asYjPByBj17yZ/1LfPM5sx5awoLhCQ== X-Google-Smtp-Source: AA0mqf4VuCjTQx1EzQp2ZWG8PsWGsHDdIjBOjeNFJK7bNHpS6s1ATzvJXRaMmwcfUypWvWZO/Dskvw== X-Received: by 2002:a05:620a:3d9:b0:6fa:5091:7ac8 with SMTP id r25-20020a05620a03d900b006fa50917ac8mr7052092qkm.372.1668799167180; Fri, 18 Nov 2022 11:19:27 -0800 (PST) Received: from joelboxx.c.googlers.com.com (228.221.150.34.bc.googleusercontent.com. [34.150.221.228]) by smtp.gmail.com with ESMTPSA id w9-20020a05620a424900b006ce2c3c48ebsm2958122qko.77.2022.11.18.11.19.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Nov 2022 11:19:26 -0800 (PST) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: Eric Dumazet , Joel Fernandes , David Ahern , "David S. Miller" , Hideaki YOSHIFUJI , Jakub Kicinski , netdev@vger.kernel.org, Paolo Abeni , rcu@vger.kernel.org, rostedt@goodmis.org, paulmck@kernel.org, fweisbec@gmail.com Subject: [PATCH v2 2/2] net: devinet: Reduce refcount before grace period Date: Fri, 18 Nov 2022 19:19:09 +0000 Message-Id: <20221118191909.1756624-2-joel@joelfernandes.org> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog In-Reply-To: <20221118191909.1756624-1-joel@joelfernandes.org> References: <20221118191909.1756624-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet Currently, the inetdev_destroy() function waits for an RCU grace period before decrementing the refcount and freeing memory. This causes a delay with a new RCU configuration that tries to save power, which results in the network interface disappearing later than expected. The resulting delay causes test failures on ChromeOS. Refactor the code such that the refcount is freed before the grace period and memory is freed after. With this a ChromeOS network test passes that does 'ip netns del' and polls for an interface disappearing, now passes. Reported-by: Joel Fernandes (Google) Signed-off-by: Eric Dumazet Signed-off-by: Joel Fernandes (Google) --- net/ipv4/devinet.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index e8b9a9202fec..b0acf6e19aed 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -234,13 +234,20 @@ static void inet_free_ifa(struct in_ifaddr *ifa) call_rcu(&ifa->rcu_head, inet_rcu_free_ifa); } +static void in_dev_free_rcu(struct rcu_head *head) +{ + struct in_device *idev = container_of(head, struct in_device, rcu_head); + + kfree(rcu_dereference_protected(idev->mc_hash, 1)); + kfree(idev); +} + void in_dev_finish_destroy(struct in_device *idev) { struct net_device *dev = idev->dev; WARN_ON(idev->ifa_list); WARN_ON(idev->mc_list); - kfree(rcu_dereference_protected(idev->mc_hash, 1)); #ifdef NET_REFCNT_DEBUG pr_debug("%s: %p=%s\n", __func__, idev, dev ? dev->name : "NIL"); #endif @@ -248,7 +255,7 @@ void in_dev_finish_destroy(struct in_device *idev) if (!idev->dead) pr_err("Freeing alive in_device %p\n", idev); else - kfree(idev); + call_rcu(&idev->rcu_head, in_dev_free_rcu); } EXPORT_SYMBOL(in_dev_finish_destroy); @@ -298,12 +305,6 @@ static struct in_device *inetdev_init(struct net_device *dev) goto out; } -static void in_dev_rcu_put(struct rcu_head *head) -{ - struct in_device *idev = container_of(head, struct in_device, rcu_head); - in_dev_put(idev); -} - static void inetdev_destroy(struct in_device *in_dev) { struct net_device *dev; @@ -328,7 +329,7 @@ static void inetdev_destroy(struct in_device *in_dev) neigh_parms_release(&arp_tbl, in_dev->arp_parms); arp_ifdown(dev); - call_rcu(&in_dev->rcu_head, in_dev_rcu_put); + in_dev_put(in_dev); } int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b) -- 2.38.1.584.g0f3c55d4c2-goog