From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Wed, 12 Sep 2018 06:51:50 +0000 (+0200)
Subject: cache.clear('name'): fix a small GC race
X-Git-Tag: v3.1.0~4^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e73af5d1b7375e446b597f28764bac21b1d676d;p=thirdparty%2Fknot-resolver.git

cache.clear('name'): fix a small GC race

Thanks to Marek for noticing it.
---

diff --git a/daemon/lua/sandbox.lua b/daemon/lua/sandbox.lua
index 131732402..f10d5a777 100644
--- a/daemon/lua/sandbox.lua
+++ b/daemon/lua/sandbox.lua
@@ -184,13 +184,13 @@ cache.clear = function (name, exact_name, rr_type, chunk_size, callback, prev_st
 		local ret = ffi.C.kr_cache_closest_apex(cach, dname, false, apex_array)
 		if ret < 0 then
 			error(ffi.string(ffi.C.knot_strerror(ret))) end
-		ffi.gc(apex_array[0], ffi.C.free)
 		if not ffi.C.knot_dname_is_equal(apex_array[0], dname) then
 			local apex_str = kres.dname2str(apex_array[0])
 			rettable.not_apex = 'to clear proofs of non-existence call '
 				.. 'cache.clear(\'' .. tostring(apex_str) ..'\')'
 			rettable.subtree = apex_str
 		end
+		ffi.C.free(apex_array[0])
 	end
 
 	if rr_type ~= nil then