Author: hselasky Date: Mon Aug 10 10:46:08 2020 New Revision: 364073 URL: https://svnweb.freebsd.org/changeset/base/364073
Log: Make sure the multicast release tasks are properly drained when destroying a VNET or a network interface. Else the inm release tasks, both IPv4 and IPv6 may cause a panic accessing a freed VNET or network interface. Reviewed by: jmg@ Discussed with: bz@ Differential Revision: https://reviews.freebsd.org/D24914 MFC after: 1 week Sponsored by: Mellanox Technologies Modified: head/sys/netinet/in.c head/sys/netinet/in_mcast.c head/sys/netinet/in_var.h head/sys/netinet6/in6_ifattach.c head/sys/netinet6/in6_mcast.c head/sys/netinet6/in6_var.h Modified: head/sys/netinet/in.c ============================================================================== --- head/sys/netinet/in.c Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet/in.c Mon Aug 10 10:46:08 2020 (r364073) @@ -998,6 +998,13 @@ in_ifdetach(struct ifnet *ifp) in_pcbpurgeif0(&V_ulitecbinfo, ifp); in_purgemaddrs(ifp); IN_MULTI_UNLOCK(); + + /* + * Make sure all multicast deletions invoking if_ioctl() are + * completed before returning. Else we risk accessing a freed + * ifnet structure pointer. + */ + inm_release_wait(NULL); } /* Modified: head/sys/netinet/in_mcast.c ============================================================================== --- head/sys/netinet/in_mcast.c Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet/in_mcast.c Mon Aug 10 10:46:08 2020 (r364073) @@ -224,18 +224,37 @@ inm_is_ifp_detached(const struct in_multi *inm) } #endif -static struct task free_task; +/* + * Interface detach can happen in a taskqueue thread context, so we must use a + * dedicated thread to avoid deadlocks when draining inm_release tasks. + */ +TASKQUEUE_DEFINE_THREAD(inm_free); +static struct task inm_free_task; static struct in_multi_head inm_free_list = SLIST_HEAD_INITIALIZER(); static void inm_release_task(void *arg __unused, int pending __unused); static void inm_init(void *arg __unused) { - TASK_INIT(&free_task, 0, inm_release_task, NULL); + TASK_INIT(&inm_free_task, 0, inm_release_task, NULL); } SYSINIT(inm_init, SI_SUB_TASKQ, SI_ORDER_ANY, inm_init, NULL); void +inm_release_wait(void *arg __unused) +{ + + /* + * Make sure all pending multicast addresses are freed before + * the VNET or network device is destroyed: + */ + taskqueue_drain(taskqueue_inm_free, &inm_free_task); +} +#ifdef VIMAGE +VNET_SYSUNINIT(inm_release_wait, SI_SUB_PROTO_DOMAIN, SI_ORDER_FIRST, inm_release_wait, NULL); +#endif + +void inm_release_list_deferred(struct in_multi_head *inmh) { @@ -244,7 +263,7 @@ inm_release_list_deferred(struct in_multi_head *inmh) mtx_lock(&in_multi_free_mtx); SLIST_CONCAT(&inm_free_list, inmh, in_multi, inm_nrele); mtx_unlock(&in_multi_free_mtx); - taskqueue_enqueue(taskqueue_thread, &free_task); + taskqueue_enqueue(taskqueue_inm_free, &inm_free_task); } void Modified: head/sys/netinet/in_var.h ============================================================================== --- head/sys/netinet/in_var.h Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet/in_var.h Mon Aug 10 10:46:08 2020 (r364073) @@ -450,6 +450,7 @@ void inm_print(const struct in_multi *); int inm_record_source(struct in_multi *inm, const in_addr_t); void inm_release_deferred(struct in_multi *); void inm_release_list_deferred(struct in_multi_head *); +void inm_release_wait(void *); struct in_multi * in_addmulti(struct in_addr *, struct ifnet *); int in_joingroup(struct ifnet *, const struct in_addr *, Modified: head/sys/netinet6/in6_ifattach.c ============================================================================== --- head/sys/netinet6/in6_ifattach.c Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet6/in6_ifattach.c Mon Aug 10 10:46:08 2020 (r364073) @@ -871,7 +871,7 @@ in6_purgemaddrs(struct ifnet *ifp) * completed before returning. Else we risk accessing a freed * ifnet structure pointer. */ - in6m_release_wait(); + in6m_release_wait(NULL); } void Modified: head/sys/netinet6/in6_mcast.c ============================================================================== --- head/sys/netinet6/in6_mcast.c Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet6/in6_mcast.c Mon Aug 10 10:46:08 2020 (r364073) @@ -539,10 +539,18 @@ in6m_release_list_deferred(struct in6_multi_head *inmh } void -in6m_release_wait(void) +in6m_release_wait(void *arg __unused) { + + /* + * Make sure all pending multicast addresses are freed before + * the VNET or network device is destroyed: + */ taskqueue_drain_all(taskqueue_in6m_free); } +#ifdef VIMAGE +VNET_SYSUNINIT(in6m_release_wait, SI_SUB_PROTO_DOMAIN, SI_ORDER_FIRST, in6m_release_wait, NULL); +#endif void in6m_disconnect_locked(struct in6_multi_head *inmh, struct in6_multi *inm) Modified: head/sys/netinet6/in6_var.h ============================================================================== --- head/sys/netinet6/in6_var.h Mon Aug 10 10:40:19 2020 (r364072) +++ head/sys/netinet6/in6_var.h Mon Aug 10 10:46:08 2020 (r364073) @@ -870,7 +870,7 @@ void in6m_commit(struct in6_multi *); void in6m_print(const struct in6_multi *); int in6m_record_source(struct in6_multi *, const struct in6_addr *); void in6m_release_list_deferred(struct in6_multi_head *); -void in6m_release_wait(void); +void in6m_release_wait(void *); void ip6_freemoptions(struct ip6_moptions *); int ip6_getmoptions(struct inpcb *, struct sockopt *); int ip6_setmoptions(struct inpcb *, struct sockopt *); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
