diff --git a/include/spdk/thread.h b/include/spdk/thread.h
index 695c8e37d..b68a73ea6 100644
--- a/include/spdk/thread.h
+++ b/include/spdk/thread.h
@@ -381,6 +381,23 @@ int spdk_thread_get_stats(struct spdk_thread_stats *stats);
  */
 int spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx);
 
+/**
+ * Send a message to the given thread. Only one critical message can be outstanding at the same
+ * time. It's intended to use this function in any cases that might interrupt the execution of the
+ * application, such as signal handlers.
+ *
+ * The message will be sent asynchronously - i.e. spdk_thread_send_critical_msg will always return
+ * prior to `fn` being called.
+ *
+ * \param thread The target thread.
+ * \param fn This function will be called on the given thread.
+ *
+ * \return 0 on success
+ * \return -EIO if the message could not be sent to the destination thread, due to an already
+ * outstanding critical message
+ */
+int spdk_thread_send_critical_msg(struct spdk_thread *thread, spdk_msg_fn fn);
+
 /**
  * Send a message to each thread, serially.
  *
diff --git a/lib/thread/thread.c b/lib/thread/thread.c
index eeea5e042..15f411666 100644
--- a/lib/thread/thread.c
+++ b/lib/thread/thread.c
@@ -34,6 +34,7 @@
 #include "spdk/stdinc.h"
 
 #include "spdk/env.h"
+#include "spdk/likely.h"
 #include "spdk/queue.h"
 #include "spdk/string.h"
 #include "spdk/thread.h"
@@ -149,6 +150,8 @@ struct spdk_thread {
 	SLIST_HEAD(, spdk_msg)		msg_cache;
 	size_t				msg_cache_count;
 
+	spdk_msg_fn			critical_msg;
+
 	/* User context allocated at the end */
 	uint8_t				ctx[0];
 };
@@ -484,6 +487,7 @@ spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now)
 	uint32_t msg_count;
 	struct spdk_thread *orig_thread;
 	struct spdk_poller *poller, *tmp;
+	spdk_msg_fn critical_msg;
 	int rc = 0;
 
 	orig_thread = _get_thread();
@@ -493,6 +497,12 @@ spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now)
 		now = spdk_get_ticks();
 	}
 
+	critical_msg = thread->critical_msg;
+	if (spdk_unlikely(critical_msg != NULL)) {
+		critical_msg(NULL);
+		thread->critical_msg = NULL;
+	}
+
 	msg_count = _spdk_msg_queue_run_batch(thread, max_msgs);
 	if (msg_count) {
 		rc = 1;
@@ -642,7 +652,8 @@ bool
 spdk_thread_is_idle(struct spdk_thread *thread)
 {
 	if (spdk_ring_count(thread->messages) ||
-	    _spdk_thread_has_unpaused_pollers(thread)) {
+	    _spdk_thread_has_unpaused_pollers(thread) ||
+	    thread->critical_msg != NULL) {
 		return false;
 	}
 
@@ -741,6 +752,19 @@ spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx
 	return 0;
 }
 
+int
+spdk_thread_send_critical_msg(struct spdk_thread *thread, spdk_msg_fn fn)
+{
+	spdk_msg_fn expected = NULL;
+
+	if (__atomic_compare_exchange_n(&thread->critical_msg, &expected, fn, false, __ATOMIC_SEQ_CST,
+					__ATOMIC_SEQ_CST)) {
+		return 0;
+	}
+
+	return -EIO;
+}
+
 struct spdk_poller *
 spdk_poller_register(spdk_poller_fn fn,
 		     void *arg,