diff --git a/banned-die.h b/banned-die.h
index cff1072397..52a93c67c6 100644
--- a/banned-die.h
+++ b/banned-die.h
@@ -17,6 +17,9 @@
 #undef xstrdup
 #define xstrdup(str) BANNED(xstrdup)
 
+#undef xcalloc
+#define xcalloc(nmemb, size) BANNED(xcalloc)
+
 #undef xstrfmt
 #define xstrfmt(...) BANNED(xstrfmt)
 
diff --git a/trace2/tr2_ctr.c b/trace2/tr2_ctr.c
index 20618a65b2..9920979030 100644
--- a/trace2/tr2_ctr.c
+++ b/trace2/tr2_ctr.c
@@ -55,7 +55,11 @@ static struct tr2_counter_metadata tr2_counter_metadata[TRACE2_NUMBER_OF_COUNTER
 void tr2_counter_increment(enum trace2_counter_id cid, uint64_t value)
 {
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
-	struct tr2_counter *c = &ctx->counter_block.counter[cid];
+	struct tr2_counter *c;
+
+	if (tr2tls_is_fallback(ctx))
+		return;
+	c = &ctx->counter_block.counter[cid];
 
 	c->value += value;
 
@@ -69,6 +73,8 @@ void tr2_update_final_counters(void)
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 	enum trace2_counter_id cid;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
 	if (!ctx->used_any_counter)
 		return;
 
@@ -90,6 +96,8 @@ void tr2_emit_per_thread_counters(tr2_tgt_evt_counter_t *fn_apply)
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 	enum trace2_counter_id cid;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
 	if (!ctx->used_any_per_thread_counter)
 		return;
 
diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
index 5e4624d0b3..ace2cd438b 100644
--- a/trace2/tr2_tls.c
+++ b/trace2/tr2_tls.c
@@ -14,6 +14,9 @@
 #define TR2_REGION_NESTING_INITIAL_SIZE (100)
 
 static struct tr2tls_thread_ctx *tr2tls_thread_main;
+static struct tr2tls_thread_ctx tr2tls_thread_fallback = {
+	.thread_name = "unknown",
+};
 static uint64_t tr2tls_us_start_process;
 
 static pthread_mutex_t tr2tls_mutex;
@@ -38,16 +41,23 @@ void tr2tls_start_process_clock(void)
 struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_base_name,
 					     uint64_t us_thread_start)
 {
-	struct tr2tls_thread_ctx *ctx = xcalloc(1, sizeof(*ctx));
+	struct tr2tls_thread_ctx *ctx = calloc(1, sizeof(*ctx));
 	struct strbuf buf = STRBUF_INIT;
 
+	if (!ctx)
+		goto fallback;
+
 	/*
 	 * Implicitly "tr2tls_push_self()" to capture the thread's start
 	 * time in array_us_start[0].  For the main thread this gives us the
 	 * application run time.
 	 */
 	ctx->alloc = TR2_REGION_NESTING_INITIAL_SIZE;
-	ctx->array_us_start = (uint64_t *)xcalloc(ctx->alloc, sizeof(uint64_t));
+	ctx->array_us_start = calloc(ctx->alloc, sizeof(uint64_t));
+	if (!ctx->array_us_start) {
+		free(ctx);
+		goto fallback;
+	}
 	ctx->array_us_start[ctx->nr_open_regions++] = us_thread_start;
 
 	ctx->thread_id = tr2tls_locked_increment(&tr2_next_thread_id);
@@ -63,6 +73,10 @@ struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_base_name,
 	pthread_setspecific(tr2tls_key, ctx);
 
 	return ctx;
+
+fallback:
+	pthread_setspecific(tr2tls_key, &tr2tls_thread_fallback);
+	return &tr2tls_thread_fallback;
 }
 
 struct tr2tls_thread_ctx *tr2tls_get_self(void)
@@ -85,6 +99,11 @@ struct tr2tls_thread_ctx *tr2tls_get_self(void)
 	return ctx;
 }
 
+int tr2tls_is_fallback(const struct tr2tls_thread_ctx *ctx)
+{
+	return ctx == &tr2tls_thread_fallback;
+}
+
 int tr2tls_is_main_thread(void)
 {
 	if (!HAVE_THREADS)
@@ -101,6 +120,9 @@ void tr2tls_unset_self(void)
 
 	pthread_setspecific(tr2tls_key, NULL);
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+
 	free((char *)ctx->thread_name);
 	free(ctx->array_us_start);
 	free(ctx);
@@ -112,6 +134,9 @@ void tr2tls_push_self(uint64_t us_now)
 	uint64_t *new_array;
 	size_t new_alloc;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+
 	if (ctx->nr_skipped_regions) {
 		ctx->nr_skipped_regions++;
 		return;
@@ -143,6 +168,9 @@ void tr2tls_pop_self(void)
 {
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+
 	if (ctx->nr_skipped_regions) {
 		ctx->nr_skipped_regions--;
 		return;
@@ -158,6 +186,9 @@ void tr2tls_pop_unwind_self(void)
 {
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+
 	while (ctx->nr_open_regions > 1)
 		tr2tls_pop_self();
 }
@@ -168,6 +199,8 @@ uint64_t tr2tls_region_elasped_self(uint64_t us)
 	uint64_t us_start;
 
 	ctx = tr2tls_get_self();
+	if (tr2tls_is_fallback(ctx))
+		return 0;
 	if (ctx->nr_skipped_regions)
 		return 0;
 	if (!ctx->nr_open_regions)
@@ -189,6 +222,10 @@ uint64_t tr2tls_absolute_elapsed(uint64_t us)
 static void tr2tls_key_destructor(void *payload)
 {
 	struct tr2tls_thread_ctx *ctx = payload;
+
+	if (tr2tls_is_fallback(ctx))
+		return;
+
 	free((char *)ctx->thread_name);
 	free(ctx->array_us_start);
 	free(ctx);
diff --git a/trace2/tr2_tls.h b/trace2/tr2_tls.h
index c365017923..4a0969c014 100644
--- a/trace2/tr2_tls.h
+++ b/trace2/tr2_tls.h
@@ -54,6 +54,12 @@ struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_base_name,
  */
 struct tr2tls_thread_ctx *tr2tls_get_self(void);
 
+/*
+ * Return true if the context is the non-allocating fallback used after an
+ * allocation failure. Callers must not modify a fallback context.
+ */
+int tr2tls_is_fallback(const struct tr2tls_thread_ctx *ctx);
+
 /*
  * return true if the current thread is the main thread.
  */
diff --git a/trace2/tr2_tmr.c b/trace2/tr2_tmr.c
index 275091c693..4dfc7afb4e 100644
--- a/trace2/tr2_tmr.c
+++ b/trace2/tr2_tmr.c
@@ -39,8 +39,11 @@ static struct tr2_timer_metadata tr2_timer_metadata[TRACE2_NUMBER_OF_TIMERS] = {
 void tr2_start_timer(enum trace2_timer_id tid)
 {
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
-	struct tr2_timer *t = &ctx->timer_block.timer[tid];
+	struct tr2_timer *t;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+	t = &ctx->timer_block.timer[tid];
 	t->recursion_count++;
 	if (t->recursion_count > 1)
 		return; /* ignore recursive starts */
@@ -51,10 +54,13 @@ void tr2_start_timer(enum trace2_timer_id tid)
 void tr2_stop_timer(enum trace2_timer_id tid)
 {
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
-	struct tr2_timer *t = &ctx->timer_block.timer[tid];
+	struct tr2_timer *t;
 	uint64_t ns_now;
 	uint64_t ns_interval;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
+	t = &ctx->timer_block.timer[tid];
 	assert(t->recursion_count > 0);
 
 	t->recursion_count--;
@@ -92,6 +98,8 @@ void tr2_update_final_timers(void)
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 	enum trace2_timer_id tid;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
 	if (!ctx->used_any_timer)
 		return;
 
@@ -138,6 +146,8 @@ void tr2_emit_per_thread_timers(tr2_tgt_evt_timer_t *fn_apply)
 	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
 	enum trace2_timer_id tid;
 
+	if (tr2tls_is_fallback(ctx))
+		return;
 	if (!ctx->used_any_per_thread_timer)
 		return;