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=-9.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 84907C6786F for ; Tue, 30 Oct 2018 13:27:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EA1D20838 for ; Tue, 30 Oct 2018 13:27:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="FPJJM+GG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4EA1D20838 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728295AbeJ3WU5 (ORCPT ); Tue, 30 Oct 2018 18:20:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:51874 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727768AbeJ3WU5 (ORCPT ); Tue, 30 Oct 2018 18:20:57 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1FD752080A; Tue, 30 Oct 2018 13:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1540906049; bh=xr6qys1tLzdVxTyuQ9ICVYPij5NuuU/hRtzp3gbIVa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FPJJM+GGe9/YIOAS2UFET/jkJHVhvb2VB3IFQjGdGSdEvv8ujuq49x87MVHOtIC3q kX6OG+iqNFXniOMvmN0RXnNduoVxILweYQONgRq5pYgaOjeL1rsRSLu8dK2V5GRyqH 8lFo/6/+EcvEZU1k8HVjFaQfCRveC8i/Fyo9zt7k= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Daniel Borkmann , Sasha Levin Subject: [PATCH AUTOSEL 4.18 09/33] xsk: do not call synchronize_net() under RCU read lock Date: Tue, 30 Oct 2018 09:26:33 -0400 Message-Id: <20181030132657.217970-9-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181030132657.217970-1-sashal@kernel.org> References: <20181030132657.217970-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Björn Töpel [ Upstream commit cee271678d0e3177a25d0fcb2fa5e051d48e4262 ] The XSKMAP update and delete functions called synchronize_net(), which can sleep. It is not allowed to sleep during an RCU read section. Instead we need to make sure that the sock sk_destruct (xsk_destruct) function is asynchronously called after an RCU grace period. Setting the SOCK_RCU_FREE flag for XDP sockets takes care of this. Fixes: fbfc504a24f5 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP") Reported-by: Eric Dumazet Signed-off-by: Björn Töpel Acked-by: Song Liu Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- kernel/bpf/xskmap.c | 10 ++-------- net/xdp/xsk.c | 2 ++ 2 files changed, 4 insertions(+), 8 deletions(-) diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c index b3c557476a8d..c98501a04742 100644 --- a/kernel/bpf/xskmap.c +++ b/kernel/bpf/xskmap.c @@ -191,11 +191,8 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value, sock_hold(sock->sk); old_xs = xchg(&m->xsk_map[i], xs); - if (old_xs) { - /* Make sure we've flushed everything. */ - synchronize_net(); + if (old_xs) sock_put((struct sock *)old_xs); - } sockfd_put(sock); return 0; @@ -211,11 +208,8 @@ static int xsk_map_delete_elem(struct bpf_map *map, void *key) return -EINVAL; old_xs = xchg(&m->xsk_map[k], NULL); - if (old_xs) { - /* Make sure we've flushed everything. */ - synchronize_net(); + if (old_xs) sock_put((struct sock *)old_xs); - } return 0; } diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 4e937cd7c17d..661504042d30 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -744,6 +744,8 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol, sk->sk_destruct = xsk_destruct; sk_refcnt_debug_inc(sk); + sock_set_flag(sk, SOCK_RCU_FREE); + xs = xdp_sk(sk); mutex_init(&xs->mutex); spin_lock_init(&xs->tx_completion_lock); -- 2.17.1