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 EF2E82E3366 for ; Thu, 3 Apr 2025 01:27:20 +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=1743643641; cv=none; b=ruZZkuYvS4PggV3slYUnj1E/SP+Gj2dtunYLeqEqstQcX/WYE1xIuhGN7WAVTLxmmyxcKx6l/WwZDDDvC2KvJTY1BTeh2fW+uHTvjIvppIcy3pqUOUeJrfp5cOnjI8T7LsLhHA/ohqmiy9vVWBz4md7nnjh/Qri56gXq8qbV+Q0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743643641; c=relaxed/simple; bh=VuBibpfHnxLv29Z/zMefbQRpw8Mybu4qWjKr090SLc4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=IWvdGyjdsdsEYsLv4tJfFQ+FH/EityfAgJ3HBlJHI01ngYY97g359WDmW2zldZWph5D9ub51pz13DaU1NI7GAgSpx+Ph994TJQkXv4srzhJ5ZmjWy0zKnzLq21dDbhIRCp9apSA83Lt7BAfCcgcjVI9BXefYZxmvp6UZYiXR5BI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YOwP5WGi; 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="YOwP5WGi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11DC5C4CEDD; Thu, 3 Apr 2025 01:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743643640; bh=VuBibpfHnxLv29Z/zMefbQRpw8Mybu4qWjKr090SLc4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YOwP5WGi8p0XbDLZK9IJ1K2kX1jObjaNfJr3CHofyWWRd1HfF/qkeNGUR3Z8zfBgl bbtaIkMuRJEYb6jpkx+zxq9g1c3iVZJcz70KV4UmTzRDzmZLAy4UcaU9heJ0xqOHgN SuuFe/fvqLI0rMvTCC2h08b5MgfQJA6hjGe44N0FsQO+1n0oI7j24JYFFRtDl3D+aT EThq0CFWUlgQQ7XmndkJMnREuyeAzf2oXY6jXRTPS8QgSi4AMwoJenxixWnIqUg6L+ AbUO+SEOz6KdlUqOq6dPTPxZTObhFFFZGl12LWwebmqZO2Uuh1yFhsL1iCyApetzTQ oYIuhNdZjFjhw== Date: Wed, 2 Apr 2025 18:27:19 -0700 From: Jakub Kicinski To: Mina Almasry , sdf@fomichev.me Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, ap420073@gmail.com, asml.silence@gmail.com, dw@davidwei.uk Subject: Re: [PATCH net 2/2] net: avoid false positive warnings in __net_mp_close_rxq() Message-ID: <20250402182719.26c390fe@kernel.org> In-Reply-To: <20250402162428.4afc90cb@kernel.org> References: <20250331194201.2026422-1-kuba@kernel.org> <20250331194308.2026940-1-kuba@kernel.org> <20250402162428.4afc90cb@kernel.org> 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 Wed, 2 Apr 2025 16:24:28 -0700 Jakub Kicinski wrote: > On Wed, 2 Apr 2025 11:52:50 -0700 Mina Almasry wrote: > > > netdev_lock(dev); > > > - __net_mp_close_rxq(dev, ifq_idx, old_p); > > > + /* Callers holding a netdev ref may get here after we already > > > + * went thru shutdown via dev_memory_provider_uninstall(). > > > + */ > > > + if (dev->reg_state <= NETREG_REGISTERED) > > > + __net_mp_close_rxq(dev, ifq_idx, old_p); > > > > Not obvious to me why this check was moved. Do you expect to call > > __net_mp_close_rxq on an unregistered netdev and expect it to succeed > > in io_uring binding or something? > > Yes, iouring state is under spin lock it can't call in here atomically. > device unregister may race with iouring shutdown. > > Now that I look at it I think we need > > diff --git a/net/core/dev.c b/net/core/dev.c > index be17e0660144..0a70080a1209 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -11947,6 +11947,7 @@ void unregister_netdevice_many_notify(struct list_head *head, > unlist_netdevice(dev); > netdev_lock(dev); > WRITE_ONCE(dev->reg_state, NETREG_UNREGISTERING); > + dev_memory_provider_uninstall(dev); > netdev_unlock(dev); > } > flush_all_backlogs(); > @@ -11961,7 +11962,6 @@ void unregister_netdevice_many_notify(struct list_head *head, > dev_tcx_uninstall(dev); > netdev_lock_ops(dev); > dev_xdp_uninstall(dev); > - dev_memory_provider_uninstall(dev); > netdev_unlock_ops(dev); > bpf_dev_bound_netdev_unregister(dev); > > since 1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") > we drop the lock after setting UNREGISTERING so we may call .uninstall > after iouring torn down its side. > > Right, Stan? Actually, if I don't split the check here things will just work. Let me do that in v2. Thanks for flagging!