Re: [Tarantool-patches] [PATCH luajit 1/2] Run VM events and finalizers in separate state.

[Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi, Sergey!
Thanks for the review!
Fixed your comment and force-pushed the branch.

On 30.03.26, Sergey Bronnikov wrote:
> Hi, Sergey!
> 
> thanks for the patch! LGTM with a minor comment below.
> 
> Sergey
> 
> On 3/28/26 18:31, Sergey Kaplun wrote:
> 
> 
> <snipped>
> 
> > diff --git a/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua b/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua
> > new file mode 100644
> > index 00000000..ad275e17
> > --- /dev/null
> > +++ b/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua
> > @@ -0,0 +1,47 @@
> > +local tap = require('tap')
> > +
> > +-- The test file to demonstrate LuaJIT crash during stack overflow
> > +-- in the VM event handle.
> > +-- See also,https://github.com/LuaJIT/LuaJIT/issues/1403.
> > +
> > +local test = tap.test('lj-1403-vmevent-crash-on-stkov'):skipcond({
> > +  ['Test requires JIT enabled'] = not jit.status(),
> > +})
> > +
> > +test:plan(1)
> > +
> > +local jit_dump = require('jit.dump')
> > +
> > +-- XXX: Some specific stack usage without a stack top check by the
> > +-- Lua function header.
> > +local t = setmetatable({}, {__newindex = pcall, __call = type})
> 
> reproduced without __call metamethod, please add a comment with explanation
> 
> why it is needed

Removed:
===================================================================
diff --git a/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua b/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua
index ad275e17..6812c330 100644
--- a/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua
+++ b/test/tarantool-tests/lj-1403-vmevent-crash-on-stkov.test.lua
@@ -14,7 +14,7 @@ local jit_dump = require('jit.dump')
 
 -- XXX: Some specific stack usage without a stack top check by the
 -- Lua function header.
-local t = setmetatable({}, {__newindex = pcall, __call = type})
+local t = setmetatable({}, {__newindex = pcall})
 -- luacheck: no unused
 local function prober(...)
   -- Invokes `pcall(t, t, t)`.
===================================================================

> 
> > +-- luacheck: no unused
> > +local function prober(...)
> > +  -- Invokes `pcall(t, t, t)`.
> > +  t[t] = t
> > +end
> > +
> > +jit.opt.start('hotloop=1')
> > +-- Need the invocation of the VM event.
> > +jit_dump.start('i', '/dev/null')
> > +
> > +-- The code below causes the stack overflow in the VM event
> > +-- handler. The unwinding of the error breaks the JIT semantics
> > +-- and leads to a crash.
> > +local function looper()
> > +  local r = pcall(prober)
> > +  if not r then
> > +    local n = 1
> > +    while n < 3 do
> > +      prober(1, 2)
> > +      n = n + 1
> > +    end
> > +  end
> > +  looper()
> > +end
> > +
> > +pcall(coroutine.wrap(looper))
> > +
> > +test:ok(true, 'no crash')
> > +
> > +test:done(true)

-- 
Best regards,
Sergey Kaplun