From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE7AE28FC for ; Sun, 11 Aug 2024 17:57:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723399046; cv=none; b=NIUpU39MNzJxUaz1yjKUeDybA7X5zCCkBAZxN8yt/sAKNZVIEe+4VUKQOgDq4Vz/nv3b+WhPfhgWsdOJ/7hmP4VO2e5sEJgzfTuGDNvJmfpVzfvJZec14i8m6WfYsVEc4Ud63J+KRTIgjMs7Qfo5DEOazcplOQMzFWImhEvFbSg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723399046; c=relaxed/simple; bh=umr0sNtpHKBBwH4G+x1qdqGhky6alTpohH2FdlnVDAA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AYJkU27EqvHMnh9SJh5RDphRD0xf9TpPcrbl8LFxlVNa4XyGHWQ+s8q0joKYXPUqdnwiUO+GsFzvwhJeNJuEgTkPBTjQNlEJtC6V0a7zaQEvVGxV53zxUmI3EuSDwaUrm1k9T9er6XNL6Zin8rT2T2lIw90cM1gYQ8v52EV9Gak= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=a+TxMG/+; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="a+TxMG/+" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1fd78c165eeso28760205ad.2 for ; Sun, 11 Aug 2024 10:57:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1723399044; x=1724003844; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=mmIOT3RGjohKgqwIouc8ZUvGmcOc7wwSjlRkZiX7GhU=; b=a+TxMG/+cyUhqmt+1Nw7XiEVBydRJHMheVX7cyziRdwP0WDbugssfeuo+ltf/pf9Kq F15+p0W2WVpFvaRR7+BpohEcKPrbpz8hPi6gDizfiZeD9TiYV/TPuOX+frUUi/+5wbr0 HeevBwOqoDJqLhKRAogloJkeaulhf4o+GUvyeehX4XlgpBGF68LiKBWdHYOZShxYEZ/c KwbOUNsAZvoKUOa8Fp+bLjdiYpkgdEi5VZiEWdl6mzOZvtQ5Uovzh6qWbPvGYsHjRkwj 1uAvzoQaymevmvcPQYMw32b3t9krhAeoek7AR0/btWkZtBl4DYSDTOED6CF+oyCVcc2U NdMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723399044; x=1724003844; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=mmIOT3RGjohKgqwIouc8ZUvGmcOc7wwSjlRkZiX7GhU=; b=Aw+aFvZZisIybdQ8AsPX++/PSUmbeUxMz9Mq+nIoq/xlkOXFqiYvuw0qGLGTfZJiXh dqGKcuEsQDm3QmSVBmT1/vHp1bw0YEsOrkGZg4dPTU5o2D5UUm4NS2YgIZWHwoRELjm6 P9W0lLGOexeXQliRXWqcWehOuo5UBi/xwXOL/IX0ttPSphTy6ySfH+BMnMAqQ/Xgkvt1 qM7nDCFiur5DkM9dw7cew+ZynQKmuwbJfla5DczcFnATvk2aaKA2hTbqxsPb7juiNv8M W+EgKSvvZrzRnUlSH7jxYY6u95xZxCB3Gh54J5fCyf7ROc9cAhZakTMvTrmKwmPEnkGj 74NA== X-Gm-Message-State: AOJu0Yw++idvHN9tmMxy/sGy5xQOGeTgdfL6v+VG62f8wAojwbNN7oiO 8ALtm7+z8JMzHA6r7I9w/pDEDIfxo4zT4IpHYIYDrSgS7C4apeqH X-Google-Smtp-Source: AGHT+IEKmmgbCinkaYqs+KbSO0cLDDIimv5mo6/JVPvpw5qR7u2nfxM41G23eWhKWUPvRUKhlAJlNg== X-Received: by 2002:a17:902:db04:b0:1fd:9420:1073 with SMTP id d9443c01a7336-200ae5cfb80mr107326125ad.43.1723399043819; Sun, 11 Aug 2024 10:57:23 -0700 (PDT) Received: from localhost ([2601:647:6881:9060:8ec7:dbc7:9efe:94d5]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-200bb9b47b3sm24930665ad.138.2024.08.11.10.57.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Aug 2024 10:57:23 -0700 (PDT) Date: Sun, 11 Aug 2024 10:57:22 -0700 From: Cong Wang To: James Chapman Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, tparkin@katalix.com, syzbot+6acef9e0a4d1f46c83d4@syzkaller.appspotmail.com, gnault@redhat.com, cong.wang@bytedance.com Subject: Re: [PATCH net] l2tp: fix lockdep splat Message-ID: References: <20240806160626.1248317-1-jchapman@katalix.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240806160626.1248317-1-jchapman@katalix.com> On Tue, Aug 06, 2024 at 05:06:26PM +0100, James Chapman wrote: > diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c > index c80ab3f26084..2e86f520f799 100644 > --- a/net/l2tp/l2tp_core.c > +++ b/net/l2tp/l2tp_core.c > @@ -86,6 +86,11 @@ > /* Default trace flags */ > #define L2TP_DEFAULT_DEBUG_FLAGS 0 > > +#define L2TP_DEPTH_NESTING 2 > +#if L2TP_DEPTH_NESTING == SINGLE_DEPTH_NESTING > +#error "L2TP requires its own lockdep subclass" > +#endif This looks a bit over-engineering. Why not just #define L2TP_DEPTH_NESTING SINGLE_DEPTH_NESTING+1? Thanks.