Re: Strange intermittent LuaJIT errors (likely my fault)

[Alexander Gladysh <agladysh@...>]

On Fri, Apr 6, 2012 at 08:37, Alexander Gladysh <agladysh@gmail.com> wrote:
> On Thu, Apr 5, 2012 at 01:54, Alexander Gladysh <agladysh@gmail.com> wrote:

>> While trying to optimize my Lua serialization library, luatexts[1],
>> I've stumbled upon this strange crash in LJ2:
>>
>> ./luajit: /usr/local/share/lua/5.1/lua-nucleo/tdeepequals.lua:0:
>> attempt to index a boolean value
>> stack traceback:
>>        /usr/local/share/lua/5.1/lua-nucleo/tdeepequals.lua: in function 'tdeepequals'
>>        /usr/local/share/lua/5.1/lua-nucleo/ensure.lua:318: in function
>> 'ensure_returns'
>>        test/test.lua:2238: in main chunk
>>        [C]: ?
>>
>> Note strangely missing line info. This happens during generative test
>> suite when I'm trying to load mutated data — so all kinds of bad
>> things may happen.
>
> Here is another kind of crash:
>
> luajit2: /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:192:
> attempt to get length of local 'keys1' (a function value)
> stack traceback:
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:192: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:186: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:186: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:186: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:207: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:203: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:107: in function
> </usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:104>
>        [C]: in function 'table_sort'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:199: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:203: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:203: in function 'tmore'
>        /usr/local/share/lua/5.1//lua-nucleo/tdeepequals.lua:227: in function
> 'tdeepequals'
>        /usr/local/share/lua/5.1//lua-nucleo/ensure.lua:318: in function
> 'ensure_returns'
>        test/test.lua:2238: in main chunk
>        [C]: ?

Ugh, that's a nasty one...

I was able to reproduce this crash outside of my mutation data set, so
it is less likely that it is some kind of memory corruption on my
side. Since the crash is intermittent, it is also less likely that my
code breaks Lua state somehow. (But, of course, all that is still
possible.)

Wrapping code in xpcall or adding some additional output seems to
prevent this bug from appearing...

Mike, any advice?

Thanks,
Alexander.