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mroute: fix locking issues

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In some cases the code may fall into deadlock.
Avoid calling epoch_wait when W-lock is taken.

Sponsored by:	Stormshield
Obtained from:	Semihalf
This commit is contained in:
Wojciech Macek 2021-08-11 09:04:20 +02:00
parent d4da692862
commit f61cb12aac
1 changed files with 29 additions and 29 deletions
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58
sys/netinet/ip_mroute.c
View file

@ -77,6 +77,7 @@ __FBSDID("$FreeBSD$");
#define _PIM_VT 1
#include <sys/types.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/stddef.h>
@ -100,6 +101,7 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/counter.h>
#include <machine/atomic.h>
#include <net/if.h>
#include <net/if_var.h>
@ -727,7 +729,7 @@ ip_mrouter_init(struct socket *so, int version)
curvnet);
V_ip_mrouter = so;
ip_mrouter_cnt++;
atomic_add_int(&ip_mrouter_cnt, 1);
/* This is a mutex required by buf_ring init, but not used internally */
mtx_init(&V_buf_ring_mtx, "mroute buf_ring mtx", NULL, MTX_DEF);
@ -750,22 +752,20 @@ X_ip_mrouter_done(void)
vifi_t vifi;
struct bw_upcall *bu;
MRW_WLOCK();
if (V_ip_mrouter == NULL) {
MRW_WUNLOCK();
if (V_ip_mrouter == NULL)
return EINVAL;
}
/*
* Detach/disable hooks to the reset of the system.
*/
V_ip_mrouter = NULL;
ip_mrouter_cnt--;
atomic_subtract_int(&ip_mrouter_cnt, 1);
V_mrt_api_config = 0;
MROUTER_WAIT();
MRW_WLOCK();
upcall_thread_shutdown = 1;
mtx_lock(&V_upcall_thread_mtx);
cv_signal(&V_upcall_thread_cv);
@ -896,25 +896,17 @@ add_vif(struct vifctl *vifcp)
struct ifnet *ifp;
int error;
MRW_WLOCK();
if (vifcp->vifc_vifi >= MAXVIFS) {
MRW_WUNLOCK();
if (vifcp->vifc_vifi >= MAXVIFS)
return EINVAL;
}
/* rate limiting is no longer supported by this code */
if (vifcp->vifc_rate_limit != 0) {
log(LOG_ERR, "rate limiting is no longer supported\n");
MRW_WUNLOCK();
return EINVAL;
}
if (!in_nullhost(vifp->v_lcl_addr)) {
MRW_WUNLOCK();
return EADDRINUSE;
}
if (in_nullhost(vifcp->vifc_lcl_addr)) {
MRW_WUNLOCK();
if (in_nullhost(vifcp->vifc_lcl_addr))
return EADDRNOTAVAIL;
}
/* Find the interface with an address in AF_INET family */
if (vifcp->vifc_flags & VIFF_REGISTER) {
@ -932,7 +924,6 @@ add_vif(struct vifctl *vifcp)
ifa = ifa_ifwithaddr((struct sockaddr *)&sin);
if (ifa == NULL) {
NET_EPOCH_EXIT(et);
MRW_WUNLOCK();
return EADDRNOTAVAIL;
}
ifp = ifa->ifa_ifp;
@ -942,7 +933,6 @@ add_vif(struct vifctl *vifcp)
if ((vifcp->vifc_flags & VIFF_TUNNEL) != 0) {
CTR1(KTR_IPMF, "%s: tunnels are no longer supported", __func__);
MRW_WUNLOCK();
return EOPNOTSUPP;
} else if (vifcp->vifc_flags & VIFF_REGISTER) {
ifp = V_multicast_register_if = if_alloc(IFT_LOOP);
@ -952,17 +942,24 @@ add_vif(struct vifctl *vifcp)
V_reg_vif_num = vifcp->vifc_vifi;
}
} else { /* Make sure the interface supports multicast */
if ((ifp->if_flags & IFF_MULTICAST) == 0) {
MRW_WUNLOCK();
if ((ifp->if_flags & IFF_MULTICAST) == 0)
return EOPNOTSUPP;
}
/* Enable promiscuous reception of all IP multicasts from the if */
error = if_allmulti(ifp, 1);
if (error) {
MRW_WUNLOCK();
if (error)
return error;
}
}
MRW_WLOCK();
if (!in_nullhost(vifp->v_lcl_addr)) {
if (ifp)
V_multicast_register_if = NULL;
MRW_WUNLOCK();
if (ifp)
if_free(ifp);
return EADDRINUSE;
}
vifp->v_flags = vifcp->vifc_flags;
@ -1014,8 +1011,11 @@ del_vif_locked(vifi_t vifi)
if (vifp->v_flags & VIFF_REGISTER) {
V_reg_vif_num = VIFI_INVALID;
if_free(V_multicast_register_if);
V_multicast_register_if = NULL;
if (vifp->v_ifp) {
if (vifp->v_ifp == V_multicast_register_if)
V_multicast_register_if = NULL;
if_free(vifp->v_ifp);
}
}
mtx_destroy(&vifp->v_spin);