From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Ying Cai , "David S. Miller" Subject: [PATCH 4.2 09/54] inet: fix races in reqsk_queue_hash_req() Date: Fri, 23 Oct 2015 10:44:45 -0700 Message-Id: <20151023174519.376508520@linuxfoundation.org> In-Reply-To: <20151023174519.086915553@linuxfoundation.org> References: <20151023174519.086915553@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 29c6852602e259d2c1882f320b29d5c3fec0de04 ] Before allowing lockless LISTEN processing, we need to make sure to arm the SYN_RECV timer before the req socket is visible in hash tables. Also, req->rsk_hash should be written before we set rsk_refcnt to a non zero value. Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer") Signed-off-by: Eric Dumazet Cc: Ying Cai Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_connection_sock.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -685,20 +685,20 @@ void reqsk_queue_hash_req(struct request req->num_timeout = 0; req->sk = NULL; + setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req); + mod_timer_pinned(&req->rsk_timer, jiffies + timeout); + req->rsk_hash = hash; + /* before letting lookups find us, make sure all req fields * are committed to memory and refcnt initialized. */ smp_wmb(); atomic_set(&req->rsk_refcnt, 2); - setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req); - req->rsk_hash = hash; spin_lock(&queue->syn_wait_lock); req->dl_next = lopt->syn_table[hash]; lopt->syn_table[hash] = req; spin_unlock(&queue->syn_wait_lock); - - mod_timer_pinned(&req->rsk_timer, jiffies + timeout); } EXPORT_SYMBOL(reqsk_queue_hash_req);