diff --git a/sys/netlink/netlink_debug.h b/sys/netlink/netlink_debug.h
--- a/sys/netlink/netlink_debug.h
+++ b/sys/netlink/netlink_debug.h
@@ -40,7 +40,10 @@
  * Generic debug
  * [nl_domain] func_name: debug text
  */
-#define	NL_LOG	RT_LOG
+#define	NL_LOG(_l, ...) do {			\
+	if (THREAD_CAN_SLEEP())			\
+		RT_LOG_##_l((_l), __VA_ARGS__);	\
+} while (0)
 
 /*
  * Logging for events specific for particular process
diff --git a/sys/netlink/netlink_generic.h b/sys/netlink/netlink_generic.h
--- a/sys/netlink/netlink_generic.h
+++ b/sys/netlink/netlink_generic.h
@@ -31,6 +31,10 @@
 #ifndef _NETLINK_NETLINK_GENERIC_H_
 #define	_NETLINK_NETLINK_GENERIC_H_
 
+#include <sys/queue.h>
+#include <sys/sdt.h>
+SDT_PROVIDER_DECLARE(netlink);
+
 #include <netlink/netlink.h>
 
 /* Base header for all of the relevant messages */
diff --git a/sys/netlink/netlink_sysevent.c b/sys/netlink/netlink_sysevent.c
--- a/sys/netlink/netlink_sysevent.c
+++ b/sys/netlink/netlink_sysevent.c
@@ -53,6 +53,9 @@
 	uint32_t id;
 } sysevent_groups[MAX_SYSEVENT_GROUPS] = {};
 
+SDT_PROBE_DEFINE4(netlink, sysevent, , send__failure, "const char *", "const char *",
+    "const char *", "const char *");
+
 static const char *devctl_systems[] = {
 	"ACPI",
 	"AEON",
@@ -84,16 +87,22 @@
 
 	if (!nl_writer_group(&nw, NLMSG_LARGE, NETLINK_GENERIC, se->id, 0,
 	    false)) {
+		SDT_PROBE4(netlink, sysevent, , send__failure, se->name,
+		    subsystem, type, data);
 		NL_LOG(LOG_DEBUG, "error allocating group writer");
 		return;
 	}
 	struct nlmsghdr hdr = { .nlmsg_type = ctrl_family_id };
 	if (!nlmsg_reply(&nw, &hdr, sizeof(struct genlmsghdr))) {
+		SDT_PROBE4(netlink, sysevent, , send__failure, se->name,
+		    subsystem, type, data);
 		return;
 	}
 
 	struct genlmsghdr *ghdr = nlmsg_reserve_object(&nw, struct genlmsghdr);
 	if (ghdr == NULL) {
+		SDT_PROBE4(netlink, sysevent, , send__failure, se->name,
+		    subsystem, type, data);
 		NL_LOG(LOG_DEBUG, "unable to allocate memory");
 		return;
 	}
@@ -127,6 +136,15 @@
 {
 	for (size_t i = 0; i < MAX_SYSEVENT_GROUPS; i++) {
 		if (sysevent_groups[i].name == NULL) {
+			/*
+			 * We can be called from non-sleepable contexts, in
+			 * which case we can't register a new event (requires
+			 * both an allocation and taking an sx in genl
+			 * registration).
+			 */
+			if (!THREAD_CAN_SLEEP())
+				break;
+
 			sysevent_new_group(i, system);
 			return (&sysevent_groups[i]);
 		}
@@ -144,6 +162,8 @@
 	struct sysevent_group *se = sysevent_get_group(system);
 
 	if (se == NULL) {
+		SDT_PROBE4(netlink, sysevent, , send__failure, system,
+		    subsystem, type, data);
 		NL_LOG(LOG_WARNING, "impossible to add the event %s, "
 		    "too many event groups\n", system);
 		return;