git: 9ce46cbc95d7 - main - ip_mroute: move ip_mrouter_done outside lock

The branch main has been updated by wma:

URL: https://cgit.FreeBSD.org/src/commit/?id=9ce46cbc95d7a6fccb55af0d42cbb85c29f10639

commit 9ce46cbc95d7a6fccb55af0d42cbb85c29f10639
Author:     Wojciech Macek <wma@FreeBSD.org>
AuthorDate: 2022-01-21 05:15:08 +0000
Commit:     Wojciech Macek <wma@FreeBSD.org>
CommitDate: 2022-01-21 05:17:19 +0000

    ip_mroute: move ip_mrouter_done outside lock
    
    X_ip_mrouter_done might sleep, which triggers INVARIANTS to
    print additional errors on the screen.
    Move it outside the lock, but provide some basic synchronization
    to avoid race condition during module uninit/unload.
    
    Obtained from:          Semihalf
    Sponsored by:           Stormshield
---
 sys/netinet/ip_mroute.c | 11 ++++++++---
 sys/netinet/ip_mroute.h |  4 +++-
 sys/netinet/raw_ip.c    | 11 ++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index 8cd0b2ac7449..0566048621ad 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -300,7 +300,7 @@ VNET_DEFINE_STATIC(struct ifnet *, multicast_register_if);
 static u_long	X_ip_mcast_src(int);
 static int	X_ip_mforward(struct ip *, struct ifnet *, struct mbuf *,
 		    struct ip_moptions *);
-static int	X_ip_mrouter_done(void);
+static int	X_ip_mrouter_done(void *);
 static int	X_ip_mrouter_get(struct socket *, struct sockopt *);
 static int	X_ip_mrouter_set(struct socket *, struct sockopt *);
 static int	X_legal_vif_num(int);
@@ -431,7 +431,7 @@ X_ip_mrouter_set(struct socket *so, struct sockopt *sopt)
 	break;
 
     case MRT_DONE:
-	error = ip_mrouter_done();
+	error = ip_mrouter_done(NULL);
 	break;
 
     case MRT_ADD_VIF:
@@ -734,7 +734,7 @@ ip_mrouter_init(struct socket *so, int version)
  * Disable multicast forwarding.
  */
 static int
-X_ip_mrouter_done(void)
+X_ip_mrouter_done(void *locked)
 {
     struct ifnet *ifp;
     u_long i;
@@ -751,6 +751,11 @@ X_ip_mrouter_done(void)
     atomic_subtract_int(&ip_mrouter_cnt, 1);
     V_mrt_api_config = 0;
 
+    if (locked) {
+	struct epoch_tracker *mrouter_et = locked;
+	MROUTER_RUNLOCK_PARAM(mrouter_et);
+    }
+
     MROUTER_WAIT();
 
     /* Stop and drain task queue */
diff --git a/sys/netinet/ip_mroute.h b/sys/netinet/ip_mroute.h
index 65c5bdd3a025..016d026d184c 100644
--- a/sys/netinet/ip_mroute.h
+++ b/sys/netinet/ip_mroute.h
@@ -363,12 +363,14 @@ struct sockopt;
 
 extern int	(*ip_mrouter_set)(struct socket *, struct sockopt *);
 extern int	(*ip_mrouter_get)(struct socket *, struct sockopt *);
-extern int	(*ip_mrouter_done)(void);
+extern int	(*ip_mrouter_done)(void *);
 extern int	(*mrt_ioctl)(u_long, caddr_t, int);
 
 #define	MROUTER_RLOCK_TRACKER	struct epoch_tracker mrouter_et
+#define	MROUTER_RLOCK_PARAM_PTR		&mrouter_et
 #define	MROUTER_RLOCK()	epoch_enter_preempt(net_epoch_preempt, &mrouter_et)
 #define	MROUTER_RUNLOCK()	epoch_exit_preempt(net_epoch_preempt, &mrouter_et)
+#define	MROUTER_RUNLOCK_PARAM(param)	epoch_exit_preempt(net_epoch_preempt, param)
 #define	MROUTER_WAIT()	epoch_wait_preempt(net_epoch_preempt)
 
 #endif /* _KERNEL */
diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c
index 7c495745806e..08ce848a63f7 100644
--- a/sys/netinet/raw_ip.c
+++ b/sys/netinet/raw_ip.c
@@ -119,7 +119,7 @@ VNET_DEFINE(struct socket *, ip_mrouter);
  */
 int (*ip_mrouter_set)(struct socket *, struct sockopt *);
 int (*ip_mrouter_get)(struct socket *, struct sockopt *);
-int (*ip_mrouter_done)(void);
+int (*ip_mrouter_done)(void *locked);
 int (*ip_mforward)(struct ip *, struct ifnet *, struct mbuf *,
 		   struct ip_moptions *);
 int (*mrt_ioctl)(u_long, caddr_t, int);
@@ -879,18 +879,23 @@ static void
 rip_detach(struct socket *so)
 {
 	struct inpcb *inp;
+	MROUTER_RLOCK_TRACKER;
 
 	inp = sotoinpcb(so);
 	KASSERT(inp != NULL, ("rip_detach: inp == NULL"));
 	KASSERT(inp->inp_faddr.s_addr == INADDR_ANY,
 	    ("rip_detach: not closed"));
 
+	/* Disable mrouter first, lock released inside ip_mrouter_done */
+	MROUTER_RLOCK();
+	if (so == V_ip_mrouter && ip_mrouter_done)
+		ip_mrouter_done(MROUTER_RLOCK_PARAM_PTR);
+
 	INP_WLOCK(inp);
 	INP_HASH_WLOCK(&V_ripcbinfo);
 	rip_delhash(inp);
 	INP_HASH_WUNLOCK(&V_ripcbinfo);
-	if (so == V_ip_mrouter && ip_mrouter_done)
-		ip_mrouter_done();
+
 	if (ip_rsvp_force_done)
 		ip_rsvp_force_done(so);
 	if (so == V_ip_rsvpd)