Hi, Sergey,

see my comments

Hi, Sergey!
Thanks for the patch!
LGTM, except 1 minor comment and 1 reminder below.

On 25.02.25, Sergey Bronnikov wrote:

The patch consolidates handling profilers errors into a single
place - in a function `prof_error()` and handles PROFILE_ERRIO,
generated in a function `misc_memprof_start`, in a `prof_error()`.
---
 src/lib_misc.c | 49 +++++++++----------------------------------------
 1 file changed, 9 insertions(+), 40 deletions(-)

diff --git a/src/lib_misc.c b/src/lib_misc.c
index b4b58509..c4b40996 100644
--- a/src/lib_misc.c
+++ b/src/lib_misc.c
@@ -286,14 +286,14 @@ static int prof_error(lua_State *L, int status, const char *err_details)
         lua_pushstring(L, err2msg(LJ_ERR_PROF_MISUSE));
       lua_pushinteger(L, EINVAL);
       return 3;
-#if LJ_HASSYSPROF
+#if LJ_HASSYSPROF || LJ_HASMEMPROF
     case PROFILE_ERRRUN:
       lua_pushnil(L);
       lua_pushstring(L, err2msg(LJ_ERR_PROF_ISRUNNING));
       lua_pushinteger(L, EINVAL);
       return 3;
     case PROFILE_ERRIO:
-      return luaL_fileresult(L, 0, NULL);
+      return luaL_fileresult(L, 0, err_details);

Discussed offline that this should be done in the previous patch-set.

 #endif

<snipped>

+  if (LJ_UNLIKELY(status == PROFILE_ERRRUN)) {
       lua_pushnil(L);
       lua_pushstring(L, err2msg(LJ_ERR_PROF_NOTRUNNING));
       lua_pushinteger(L, EINVAL);
       return 3;
-    case PROFILE_ERRIO:
-      return luaL_fileresult(L, 0, NULL);
-#endif
-    default:
-      lj_assertL(0, "bad memprof error %d", status);
-      return 0;
-    }
   }
+  if (LJ_UNLIKELY(status != PROFILE_SUCCESS))

Minor: Looks like more natural to use `else if` here?
Feel free to ignore.

Fixed:

--- a/src/lib_misc.c
+++ b/src/lib_misc.c
@@ -443,9 +443,9 @@ LJLIB_CF(misc_memprof_stop)
       lua_pushstring(L, err2msg(LJ_ERR_PROF_NOTRUNNING));
       lua_pushinteger(L, EINVAL);
       return 3;
-  }
-  if (LJ_UNLIKELY(status != PROFILE_SUCCESS))
+  } else if (LJ_UNLIKELY(status != PROFILE_SUCCESS)) {
     return prof_error(L, status, NULL);
+  }
 
   lua_pushboolean(L, 1);
   return 1;

+    return prof_error(L, status, NULL);
+
   lua_pushboolean(L, 1);
   return 1;
 #endif /* !LJ_HASMEMPROF */
-- 
2.43.0