From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6809A157A72 for ; Fri, 16 May 2025 02:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747362971; cv=none; b=To2N9taV5njKA2ovDPRm7HPKB34Gmv9vCOh22Pa6ODD9VEVVQevhH3iL7tjY5XWL98iPPRuJ0+KGnH3lj8YOL8kVh294wr6Uzs2kriObgKzoVHqRUL65IesLD5uTgkK2ziUNFUNHnRtMFAzy9n/v8W9i1bhUERDxSMFZtyY6mHU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747362971; c=relaxed/simple; bh=7lct8O6mJswgOdTwBIRtg+wZI8EOJpAs/M9T2luQz3o=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Ia8HlrHJ3eR7g2eBf7gAJbe+z9JU9C3gk2Qwd/kQBVE5agHaHenNOByTQaZGZnYf4udukmiTUykhrGdnLby2vp2I98Irk/iO/Bsg5DJUT97UdqRtsmA8fZl0gOzQ8K4qFut7LI+NrV4RigrBkRwKbdgl7dQiM6lgGa4kTVs4WrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VAoxE5I5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VAoxE5I5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78CA6C4CEE7; Fri, 16 May 2025 02:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747362970; bh=7lct8O6mJswgOdTwBIRtg+wZI8EOJpAs/M9T2luQz3o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VAoxE5I5+GtwtT8Jhbc7PHAK/ZfS7lB4pEHmbpGeCpltcYdGyU0oXkKAySuXknpUN HC6j1gEbcfDRhgq9L9iZZFgvUSq1MNmH7TxhbU7/Neou6Vdz5EfRow7AEUaUBU6N0A ycvQoLC2w+lGjQzWh7pdgTh24vkADXg8Vs4u39/z7bmlYVS0nMvu6q25/dlPK93wLW wPtJdTrhdsi6L6JeYTfP24i2UYs0tBWA3/Uf62Wp/PAjYZoMiXuPmiJqEFfJA0pQhZ 1tnTzhbRH0mtO657C5M0sJjYe+r38P55LvruMbjjoar3E3hW/AD8eWpP7SIk/ZYA+C b/0zE970G1o3g== Date: Thu, 15 May 2025 19:36:09 -0700 From: Jakub Kicinski To: Kuniyuki Iwashima Cc: , , , , , , Subject: Re: [PATCH net-next] net: let lockdep compare instance locks Message-ID: <20250515193609.3da84ac3@kernel.org> In-Reply-To: <20250516015114.40011-1-kuniyu@amazon.com> References: <20250516012459.1385997-1-kuba@kernel.org> <20250516015114.40011-1-kuniyu@amazon.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-Transfer-Encoding: 7bit On Thu, 15 May 2025 18:49:07 -0700 Kuniyuki Iwashima wrote: > > +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL > > + /* It's okay to use per-netns rtnl_lock if devices share netns */ > > + if (net_eq(dev_net(dev_a), dev_net(dev_b)) && > > + lockdep_rtnl_net_is_held(dev_net(dev_a))) > > Do we need > > !from_cleanup_net() > > before lockdep_rtnl_net_is_held() ? > > __rtnl_net_lock() is not held in ops_exit_rtnl_list() and > default_device_exit_batch() when calling unregister_netdevice_many(). Or do we need if (from_cleanup_net()) return -1; ? Is the thinking that once the big rtnl lock disappears in cleanup_net the devices are safe to destroy without any locking because there can't be any live users trying to access them?