Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753128Ab2F1Ngv (ORCPT ); Thu, 28 Jun 2012 09:36:51 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:34559 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827Ab2F1Ngt (ORCPT ); Thu, 28 Jun 2012 09:36:49 -0400 From: Xiaotian Feng To: netdev@vger.kernel.org, lvs-devel@vger.kernel.org, netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org, coreteam@netfilter.org Cc: linux-kernel@vger.kernel.org, Xiaotian Feng , Xiaotian Feng , Wensong Zhang , Simon Horman , Julian Anastasov , Pablo Neira Ayuso , Patrick McHardy , "David S. Miller" Subject: [RFC PATCH net-next] ipvs: add missing lock in ip_vs_ftp_init_conn() Date: Thu, 28 Jun 2012 21:36:27 +0800 Message-Id: <1340890587-8169-1-git-send-email-xtfeng@gmail.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3269 Lines: 73 We met a kernel panic in 2.6.32.43 kernel: [2680191.848044] IPVS: ip_vs_conn_hash(): request for already hashed, called from run_timer_softirq+0x175/0x1d0 [2680311.849009] general protection fault: 0000 [#1] SMP [2680311.853001] RIP: 0010:[] [] ip_vs_conn_expire+0xdc/0x2f0 [2680311.853001] RSP: 0018:ffff880028303e70 EFLAGS: 00010202 [2680311.853001] RAX: dead000000200200 RBX: ffff8801aad00b80 RCX: 0000000000001d90 [2680311.853001] RDX: dead000000100100 RSI: 000000004fd59800 RDI: ffff8801aad00c08 [2680311.853001] Call Trace: [2680311.853001] [2680311.853001] [] ? ip_vs_conn_expire+0x0/0x2f0 [2680311.853001] [] run_timer_softirq+0x175/0x1d0 [2680311.853001] [] ? lapic_next_event+0x18/0x20 [2680311.853001] [] __do_softirq+0xb3/0x150 [2680311.853001] [] call_softirq+0x1c/0x30 [2680311.853001] [] do_softirq+0x4a/0x80 [2680311.853001] [] irq_exit+0x77/0x80 [2680311.853001] [] smp_apic_timer_interrupt+0x6c/0xa0 [2680311.853001] [] apic_timer_interrupt+0x13/0x20 [2680311.853001] [2680311.853001] [] ? mwait_idle+0x52/0x70 [2680311.853001] [] ? enter_idle+0x20/0x30 [2680311.853001] [] ? cpu_idle+0x52/0x80 [2680311.853001] [] ? start_secondary+0x19d/0x280 rax and rdx is LIST_POISON1 and LIST_POISON2, so kernel is list_del() on an already deleted connection and result the general protect fault. The "request for already hashed" warning, told us someone might change the connection flags incorrectly, like described in commit aea9d711, it changes the connection flags, but doesn't put the connection back to the list. So ip_vs_conn_hash() throw a warning and return. Later, when ip_vs_conn_expire fire again, ip_vs_conn_unhash() will find the HASHED connection and list_del() it, then kernel panic happened. After code review, the only chance that kernel change connection flag without protection is in ip_vs_ftp_init_conn(). Signed-off-by: Xiaotian Feng Cc: Wensong Zhang Cc: Simon Horman Cc: Julian Anastasov Cc: Pablo Neira Ayuso Cc: Patrick McHardy Cc: "David S. Miller" --- net/netfilter/ipvs/ip_vs_ftp.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c index b20b29c..c2bc264 100644 --- a/net/netfilter/ipvs/ip_vs_ftp.c +++ b/net/netfilter/ipvs/ip_vs_ftp.c @@ -65,8 +65,10 @@ static int ip_vs_ftp_pasv; static int ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp) { + spin_lock(&cp->lock); /* We use connection tracking for the command connection */ cp->flags |= IP_VS_CONN_F_NFCT; + spin_unlock(&cp->lock); return 0; } -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/