From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40446 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752032AbbJQXmy (ORCPT ); Sat, 17 Oct 2015 19:42:54 -0400 Subject: Patch "inet: fix potential deadlock in reqsk_queue_unlink()" has been added to the 4.1-stable tree To: edumazet@google.com, andre@tomt.net, ccaputo@alt.net, davem@davemloft.net, gregkh@linuxfoundation.org, holger.hoffstaette@googlemail.com Cc: , From: Date: Sat, 17 Oct 2015 16:42:53 -0700 Message-ID: <14451253735536@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled inet: fix potential deadlock in reqsk_queue_unlink() to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: inet-fix-potential-deadlock-in-reqsk_queue_unlink.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 13 Aug 2015 15:44:51 -0700 Subject: inet: fix potential deadlock in reqsk_queue_unlink() From: Eric Dumazet commit 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af upstream. When replacing del_timer() with del_timer_sync(), I introduced a deadlock condition : reqsk_queue_unlink() is called from inet_csk_reqsk_queue_drop() inet_csk_reqsk_queue_drop() can be called from many contexts, one being the timer handler itself (reqsk_timer_handler()). In this case, del_timer_sync() loops forever. Simple fix is to test if timer is pending. Fixes: 2235f2ac75fd ("inet: fix races with reqsk timers") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Cc: Holger Hoffstätte Cc: Andre Tomt Cc: Chris Caputo Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_connection_sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -584,7 +584,7 @@ static bool reqsk_queue_unlink(struct re } spin_unlock(&queue->syn_wait_lock); - if (del_timer_sync(&req->rsk_timer)) + if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) reqsk_put(req); return found; } Patches currently in stable-queue which might be from edumazet@google.com are queue-4.1/inet-fix-potential-deadlock-in-reqsk_queue_unlink.patch