From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] sock: reset sk_err for ICMP packets read from error queue Date: Fri, 02 Dec 2016 10:56:04 -0500 (EST) Message-ID: <20161202.105604.570057839407725973.davem@davemloft.net> References: <1480532468-1610-1-git-send-email-soheil.kdev@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, edumazet@google.com, willemb@google.com, maze@google.com, hannes@stressinduktion.org, soheil@google.com To: soheil.kdev@gmail.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:35754 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbcLBP4G (ORCPT ); Fri, 2 Dec 2016 10:56:06 -0500 In-Reply-To: <1480532468-1610-1-git-send-email-soheil.kdev@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Soheil Hassas Yeganeh Date: Wed, 30 Nov 2016 14:01:08 -0500 > From: Soheil Hassas Yeganeh > > Only when ICMP packets are enqueued onto the error queue, > sk_err is also set. Before f5f99309fa74 (sock: do not set sk_err > in sock_dequeue_err_skb), a subsequent error queue read > would set sk_err to the next error on the queue, or 0 if empty. > As no error types other than ICMP set this field, sk_err should > not be modified upon dequeuing them. > > Only for ICMP errors, reset the (racy) sk_err. Some applications, > like traceroute, rely on it and go into a futile busy POLLERR > loop otherwise. > > In principle, sk_err has to be set while an ICMP error is queued. > Testing is_icmp_err_skb(skb_next) approximates this without > requiring a full queue walk. Applications that receive both ICMP > and other errors cannot rely on this legacy behavior, as other > errors do not set sk_err in the first place. > > Fixes: f5f99309fa74 (sock: do not set sk_err in sock_dequeue_err_skb) > Signed-off-by: Soheil Hassas Yeganeh > Signed-off-by: Willem de Bruijn Applied, thanks.