From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760462Ab3B0AJ3 (ORCPT ); Tue, 26 Feb 2013 19:09:29 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42953 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760341Ab3B0AJ0 (ORCPT ); Tue, 26 Feb 2013 19:09:26 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tommi Rantala , Eric Dumazet , Pavel Emelyanov , "David S. Miller" Subject: [ 71/86] net: fix infinite loop in __skb_recv_datagram() Date: Tue, 26 Feb 2013 16:08:19 -0800 Message-Id: <20130226235920.306125735@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130226235912.881663118@linuxfoundation.org> References: <20130226235912.881663118@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 77c1090f94d1b0b5186fb13a1b71b47b1343f87f ] Tommi was fuzzing with trinity and reported the following problem : commit 3f518bf745 (datagram: Add offset argument to __skb_recv_datagram) missed that a raw socket receive queue can contain skbs with no payload. We can loop in __skb_recv_datagram() with MSG_PEEK mode, because wait_for_packet() is not prepared to skip these skbs. [ 83.541011] INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 0, t=26002 jiffies, g=27673, c=27672, q=75) [ 83.541011] INFO: Stall ended before state dump start [ 108.067010] BUG: soft lockup - CPU#0 stuck for 22s! [trinity-child31:2847] ... [ 108.067010] Call Trace: [ 108.067010] [] __skb_recv_datagram+0x1a3/0x3b0 [ 108.067010] [] skb_recv_datagram+0x2d/0x30 [ 108.067010] [] rawv6_recvmsg+0xad/0x240 [ 108.067010] [] sock_common_recvmsg+0x34/0x50 [ 108.067010] [] sock_recvmsg+0xbc/0xf0 [ 108.067010] [] sys_recvfrom+0xde/0x150 [ 108.067010] [] system_call_fastpath+0x16/0x1b Reported-by: Tommi Rantala Tested-by: Tommi Rantala Signed-off-by: Eric Dumazet Cc: Pavel Emelyanov Acked-by: Pavel Emelyanov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/datagram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -187,7 +187,7 @@ struct sk_buff *__skb_recv_datagram(stru skb_queue_walk(queue, skb) { *peeked = skb->peeked; if (flags & MSG_PEEK) { - if (*off >= skb->len) { + if (*off >= skb->len && skb->len) { *off -= skb->len; continue; }