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Date:      Mon, 25 Nov 2013 20:20:34 +0000 (UTC)
From:      Craig Rodrigues <rodrigc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r258588 - head/sys/netpfil/ipfw
Message-ID:  <201311252020.rAPKKYsH021362@svn.freebsd.org>
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Author: rodrigc
Date: Mon Nov 25 20:20:34 2013
New Revision: 258588
URL: http://svnweb.freebsd.org/changeset/base/258588

Log:
  In sys/netpfil/ipfw/ip_fw_nat.c:vnet_ipfw_nat_uninit() we call "IPFW_WLOCK(chain);".
  This lock gets deleted in sys/netpfil/ipfw/ip_fw2.c:vnet_ipfw_uninit().
  
  Therefore, vnet_ipfw_nat_uninit() *must* be called before vnet_ipfw_uninit(),
  but this doesn't always happen, because the VNET_SYSINIT order is the same for both functions.
  In sys/net/netpfil/ipfw/ip_fw2.c and sys/net/netpfil/ipfw/ip_fw_nat.c,
  IPFW_SI_SUB_FIREWALL == IPFW_NAT_SI_SUB_FIREWALL == SI_SUB_PROTO_IFATTACHDOMAIN
  and
  IPFW_MODULE_ORDER == IPFW_NAT_MODULE_ORDER
  
  Consequently, if VIMAGE is enabled, and jails are created and destroyed,
  the system sometimes crashes, because we are trying to use a deleted lock.
  
  To reproduce the problem:
    (1)  Take a GENERIC kernel config, and add options for: VIMAGE, WITNESS,
         INVARIANTS.
    (2)  Run this command in a loop:
         jail -l -u root -c path=/ name=foo persist vnet && jexec foo ifconfig lo0 127.0.0.1/8 && jail -r foo
  
         (see http://lists.freebsd.org/pipermail/freebsd-current/2010-November/021280.html )
  
  Fix the problem by increasing the value of IPFW_NAT_SI_SUB_FIREWALL,
  so that vnet_ipfw_nat_uninit() runs after vnet_ipfw_uninit().

Modified:
  head/sys/netpfil/ipfw/ip_fw_nat.c

Modified: head/sys/netpfil/ipfw/ip_fw_nat.c
==============================================================================
--- head/sys/netpfil/ipfw/ip_fw_nat.c	Mon Nov 25 20:17:55 2013	(r258587)
+++ head/sys/netpfil/ipfw/ip_fw_nat.c	Mon Nov 25 20:20:34 2013	(r258588)
@@ -676,7 +676,7 @@ static moduledata_t ipfw_nat_mod = {
 };
 
 /* Define startup order. */
-#define	IPFW_NAT_SI_SUB_FIREWALL	SI_SUB_PROTO_IFATTACHDOMAIN
+#define	IPFW_NAT_SI_SUB_FIREWALL	(SI_SUB_PROTO_IFATTACHDOMAIN + 1)
 #define	IPFW_NAT_MODEVENT_ORDER		(SI_ORDER_ANY - 255)
 #define	IPFW_NAT_MODULE_ORDER		(IPFW_NAT_MODEVENT_ORDER + 1)
 #define	IPFW_NAT_VNET_ORDER		(IPFW_NAT_MODEVENT_ORDER + 2)

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