Hi, Sergey,

the patch series was rebased to the master branch (tarantool/master)

without conflicts.

Sergey

Hi, Sergey!
Thanks for the patch!
LGTM, with a few nits regarding the commit message and 1 ignorable
comment to the code style.

On 25.02.25, Sergey Bronnikov wrote:

The function `misc.sysprof.stop()` reports that profiler is

Typo: s/profiler/the profiler/

already running:

| $ ./src/luajit -e 'print(misc.sysprof.stop())'
| nil     profiler is running already     22

both in `sysprof_error()` and fixes aforementioned problem.

Don't get this sentence.

Missed this comment.

Now commit message is updated, new version is below:

Author: Sergey Bronnikov <sergeyb@tarantool.org>
Date:   Tue Feb 4 11:48:05 2025 +0300

    sysprof: fix a message with stop without run
    
    When sysprof is not started the function `misc.sysprof.stop()`
    reports that profiler is already running:
    
    | $ ./src/luajit -e 'print(misc.sysprof.stop())'
    | nil     profiler is running already     22
    
    The patch fixes that:
    
    | $ ./src/luajit -e 'print(misc.sysprof.stop())'
    | nil     profiler is not running         22
    
    Follows up tarantool/tarantool#781

Typo: s/aforementioned/the aforementioned/

Follows up tarantool/tarantool#781
---
 src/lib_misc.c                                              | 6 ++++++
 .../tarantool-tests/profilers/misclib-sysprof-lapi.test.lua | 5 +++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/lib_misc.c b/src/lib_misc.c
index c4b40996..74888d20 100644
--- a/src/lib_misc.c
+++ b/src/lib_misc.c
@@ -335,6 +335,12 @@ LJLIB_CF(misc_sysprof_stop)
   return prof_error(L, PROFILE_ERRUSE, err_details);
 #else
   int status = luaM_sysprof_stop(L);
+  if (LJ_UNLIKELY(status == PROFILE_ERRRUN)) {
+      lua_pushnil(L);
+      lua_pushstring(L, err2msg(LJ_ERR_PROF_NOTRUNNING));
+      lua_pushinteger(L, EINVAL);
+      return 3;
+  }
   if (LJ_UNLIKELY(status != PROFILE_SUCCESS))

It looks like more natural now to use else if here now.

     return prof_error(L, status, NULL);
 
diff --git a/test/tarantool-tests/profilers/misclib-sysprof-lapi.test.lua b/test/tarantool-tests/profilers/misclib-sysprof-lapi.test.lua
index ebd80cf6..770b5736 100644
--- a/test/tarantool-tests/profilers/misclib-sysprof-lapi.test.lua
+++ b/test/tarantool-tests/profilers/misclib-sysprof-lapi.test.lua

<snipped>

-- 
2.43.0