diff --git a/src/hlua.c b/src/hlua.c
index 2339711a3..216d73a39 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -9649,11 +9649,13 @@ static struct task *hlua_event_runner(struct task *task, void *context, unsigned
 
 		/* The following Lua calls can fail. */
 		if (!SET_SAFE_LJMP(hlua_sub->hlua)) {
+			hlua_lock(hlua_sub->hlua);
 			if (lua_type(hlua_sub->hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(hlua_sub->hlua->T, -1);
 			else
 				error = "critical error";
 			ha_alert("Lua event_hdl: %s.\n", error);
+			hlua_unlock(hlua_sub->hlua);
 			goto skip_event;
 		}
 
@@ -9944,11 +9946,13 @@ static int hlua_sample_conv_wrapper(const struct arg *arg_p, struct sample *smp,
 
 		/* The following Lua calls can fail. */
 		if (!SET_SAFE_LJMP(stream->hlua)) {
+			hlua_lock(stream->hlua);
 			if (lua_type(stream->hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(stream->hlua->T, -1);
 			else
 				error = "critical error";
 			SEND_ERR(stream->be, "Lua converter '%s': %s.\n", fcn->name, error);
+			hlua_unlock(stream->hlua);
 			return 0;
 		}
 
@@ -10069,11 +10073,13 @@ static int hlua_sample_fetch_wrapper(const struct arg *arg_p, struct sample *smp
 
 		/* The following Lua calls can fail. */
 		if (!SET_SAFE_LJMP(stream->hlua)) {
+			hlua_lock(stream->hlua);
 			if (lua_type(stream->hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(stream->hlua->T, -1);
 			else
 				error = "critical error";
 			SEND_ERR(smp->px, "Lua sample-fetch '%s': %s.\n", fcn->name, error);
+			hlua_unlock(stream->hlua);
 			return 0;
 		}
 
@@ -10399,12 +10405,14 @@ static enum act_return hlua_action(struct act_rule *rule, struct proxy *px,
 
 		/* The following Lua calls can fail. */
 		if (!SET_SAFE_LJMP(s->hlua)) {
+			hlua_lock(s->hlua);
 			if (lua_type(s->hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(s->hlua->T, -1);
 			else
 				error = "critical error";
 			SEND_ERR(px, "Lua function '%s': %s.\n",
 			         rule->arg.hlua_rule->fcn->name, error);
+			hlua_unlock(s->hlua);
 			goto end;
 		}
 
@@ -10585,12 +10593,14 @@ static int hlua_applet_tcp_init(struct appctx *ctx)
 
 	/* The following Lua calls can fail. */
 	if (!SET_SAFE_LJMP(hlua)) {
+		hlua_lock(hlua);
 		if (lua_type(hlua->T, -1) == LUA_TSTRING)
 			error = hlua_tostring_safe(hlua->T, -1);
 		else
 			error = "critical error";
 		SEND_ERR(strm->be, "Lua applet tcp '%s': %s.\n",
 		         ctx->rule->arg.hlua_rule->fcn->name, error);
+		hlua_unlock(hlua);
 		return -1;
 	}
 
@@ -10776,12 +10786,14 @@ static int hlua_applet_http_init(struct appctx *ctx)
 
 	/* The following Lua calls can fail. */
 	if (!SET_SAFE_LJMP(hlua)) {
+		hlua_lock(hlua);
 		if (lua_type(hlua->T, -1) == LUA_TSTRING)
 			error = hlua_tostring_safe(hlua->T, -1);
 		else
 			error = "critical error";
 		SEND_ERR(strm->be, "Lua applet http '%s': %s.\n",
 		         ctx->rule->arg.hlua_rule->fcn->name, error);
+		hlua_unlock(hlua);
 		return -1;
 	}
 
@@ -11416,11 +11428,13 @@ static int hlua_cli_parse_fct(char **args, char *payload, struct appctx *appctx,
 
 	/* The following Lua calls can fail. */
 	if (!SET_SAFE_LJMP(hlua)) {
+		hlua_lock(hlua);
 		if (lua_type(hlua->T, -1) == LUA_TSTRING)
 			error = hlua_tostring_safe(hlua->T, -1);
 		else
 			error = "critical error";
 		SEND_ERR(NULL, "Lua cli '%s': %s.\n", fcn->name, error);
+		hlua_unlock(hlua);
 		goto error;
 	}
 
@@ -11873,11 +11887,13 @@ static int hlua_filter_new(struct stream *s, struct filter *filter)
 		if (!SET_SAFE_LJMP(s->hlua)) {
 			const char *error;
 
+			hlua_lock(s->hlua);
 			if (lua_type(s->hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(s->hlua->T, -1);
 			else
 				error = "critical error";
 			SEND_ERR(s->be, "Lua filter '%s': %s.\n", conf->reg->name, error);
+			hlua_unlock(s->hlua);
 			ret = 0;
 			goto end;
 		}
@@ -12009,11 +12025,13 @@ static int hlua_filter_callback(struct stream *s, struct filter *filter, const c
 		if (!SET_SAFE_LJMP(flt_hlua)) {
 			const char *error;
 
+			hlua_lock(flt_hlua);
 			if (lua_type(flt_hlua->T, -1) == LUA_TSTRING)
 				error = hlua_tostring_safe(flt_hlua->T, -1);
 			else
 				error = "critical error";
 			SEND_ERR(s->be, "Lua filter '%s': %s.\n", conf->reg->name, error);
+			hlua_unlock(flt_hlua);
 			goto end;
 		}