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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 C140FC54FCB for ; Sun, 26 Apr 2020 19:58:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96D0D2087E for ; Sun, 26 Apr 2020 19:58:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="DGuTRLwA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726179AbgDZT6f (ORCPT ); Sun, 26 Apr 2020 15:58:35 -0400 Received: from mail.zx2c4.com ([192.95.5.64]:36819 "EHLO mail.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726171AbgDZT6e (ORCPT ); Sun, 26 Apr 2020 15:58:34 -0400 Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 2286339d; Sun, 26 Apr 2020 19:47:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=mime-version :references:in-reply-to:from:date:message-id:subject:to:cc :content-type; s=mail; bh=Tji6nhcoiQ4mNmbOVGUplvpgPlU=; b=DGuTRL wAO4D7sQUj9rbyz5PQi4REziJ46zX8MAl/xxRdTvZs2GH1bzQEziClrBWTGpuSkw DPpoKoZR4iViGSmbg66NJO6XCo7IITjOxhlf7+2dmnasfxtwXGznREWzMVa1QbK+ Sa0fFXVJc5XAPokH8Unv4P8r9iAa2kYN4xTQOU0QC89t8QW3RYSCcI8xXRfmwqb8 RYK8R36Lqs8LKbUEzkbEJRrqxHIIdt+ccEchMmBIJw0bcUElJVsb1BAB/zewQuaJ 9yPA/s/jJdX9fjxGevj7o5Ak9Tdr1N+IpuNsChcFuo76b7u3kw4WW9nKKic99m3T DRKjz9W+M5OZHF4A== Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id e650dba7 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sun, 26 Apr 2020 19:47:07 +0000 (UTC) Received: by mail-io1-f53.google.com with SMTP id e9so16582671iok.9; Sun, 26 Apr 2020 12:58:32 -0700 (PDT) X-Gm-Message-State: AGi0PuZckDh7XgB7kdP5EAVLDndxt1+eDBhH863a3APzR0tnXrJXwrMf b5gP1fTdUZ9baPwdhSELyA7vC+JGJzB+0ZguzpQ= X-Google-Smtp-Source: APiQypJhlOdeUIY7eyvappiPYS4AodHmJxQ4hDLTjQ93EdBxFvUDW6WI3qbfdHV2mBNdM+uKlj5w7Qt4ca+CDLryJek= X-Received: by 2002:a6b:7114:: with SMTP id q20mr17580244iog.79.1587931111259; Sun, 26 Apr 2020 12:58:31 -0700 (PDT) MIME-Version: 1.0 References: <0000000000005fd19505a4355311@google.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Sun, 26 Apr 2020 13:58:20 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: INFO: rcu detected stall in wg_packet_tx_worker To: Eric Dumazet Cc: syzbot , David Miller , Florian Fainelli , Greg Kroah-Hartman , jhs@mojatatu.com, =?UTF-8?B?SmnFmcOtIFDDrXJrbw==?= , Krzysztof Kozlowski , kuba@kernel.org, kvalo@codeaurora.org, leon@kernel.org, LKML , linux-kselftest@vger.kernel.org, Netdev , Shuah Khan , syzkaller-bugs@googlegroups.com, Thomas Gleixner , vivien.didelot@gmail.com, Cong Wang Content-Type: text/plain; charset="UTF-8" Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Sun, Apr 26, 2020 at 1:52 PM Jason A. Donenfeld wrote: > > It looks like part of the issue might be that I call > udp_tunnel6_xmit_skb while holding rcu_read_lock_bh, in > drivers/net/wireguard/socket.c. But I think there's good reason to do > so, and udp_tunnel6_xmit_skb should be rcu safe. In fact, > every.single.other user of udp_tunnel6_xmit_skb in the kernel uses it > with rcu locked. So, hm... In the syzkaller log, it looks like several runs are hitting: run #0: crashed: INFO: rcu detected stall in netlink_sendmsg And other runs are hitting yet different functions. So actually, it's not clear that this is the fault of the call to udp_tunnel6_xmit_skb.