[tarantool-patches] Re: [PATCH] Fix premature cdata collecting in luaT_pusherror()
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Fri Dec 7 23:42:31 MSK 2018
On 07/12/2018 21:15, Alexander Turenko wrote:
> This is follow up of 28c7e667aee9be8c3288597bcc179d9b4e7b4940 to fix
> luaT_pusherror() itself, not only luaT_error().
>
> Fixes #1955 (again).
>
> It is backport of 480868ff8f304ead2fd03e317902a1e8d41c6248 for 1.10.
> ---
>
> https://github.com/tarantool/tarantool/issues/1955
> https://github.com/tarantool/tarantool/tree/Totktonada/gh-1955-fix-luaT_pusherror-1.10
>
> src/lua/utils.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/src/lua/utils.c b/src/lua/utils.c
> index 27772a9d3..b05d16a73 100644
> --- a/src/lua/utils.c
> +++ b/src/lua/utils.c
> @@ -898,12 +898,20 @@ luaL_error_gc(struct lua_State *L)
> void
> luaT_pusherror(struct lua_State *L, struct error *e)
> {
> + /*
> + * gh-1955 luaT_pusherror allocates Lua objects, thus it
Sorry, but usually we do not mention issue numbers in comments.
Please, reword the comment so as to do not use explicit issue
number.
> + * may trigger GC. GC may invoke finalizers which are
> + * arbitrary Lua code, potentially invalidating last error
> + * object, hence error_ref below.
> + *
> + * It also important to reference the error first and only
> + * then set the finalizer.
> + */
> + error_ref(e);
> assert(CTID_CONST_STRUCT_ERROR_REF != 0);
> struct error **ptr = (struct error **) luaL_pushcdata(L,
> CTID_CONST_STRUCT_ERROR_REF);
> *ptr = e;
> - /* The order is important - first reference the error, then set gc */
> - error_ref(e);
> lua_pushcfunction(L, luaL_error_gc);
> luaL_setcdatagc(L, -2);
> }
> @@ -913,15 +921,7 @@ luaT_error(lua_State *L)
> {
> struct error *e = diag_last_error(&fiber()->diag);
> assert(e != NULL);
> - /*
> - * gh-1955 luaT_pusherror allocates Lua objects, thus it may trigger
> - * GC. GC may invoke finalizers which are arbitrary Lua code,
> - * potentially invalidating last error object, hence error_ref
> - * below.
> - */
> - error_ref(e);
> luaT_pusherror(L, e);
> - error_unref(e);
> lua_error(L);
> unreachable();
> return 0;
>
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