Re: __tostring recursion crash on windows
- From: Mike Pall <mike-1403@xxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Tue, 25 Mar 2014 11:03:12 +0100
Simon Schick wrote:
> Now at first glance it seems to make sense to crash, stack overflow, so I
> ran the code in a LuaJIT(latest build 32bit) shell, and it crashed as
> expected.
>
> Then I tried to run it in a Lua shell(5.1.4) and I got a stack overflow
> error, no crash.
>
> So I assume this is a specific LuaJIT issue.
LuaJIT limits recursion depth by checking for the number of
elements in the Lua stack, not by the number of frames. That
allows a much higher recursion depth than Lua.
But it looks like the default C stack on Win32 is rather small. So
for this example the C stack overflows before the Lua stack
overflows. A Lua stack overflow would be caught and properly
reported. But a C stack overflow leads to a crash.
I'm not sure how to check for this case or how to avoid this in
general. There are various other ways to overflow the C stack, so
just fixing this one case doesn't do much.
There's no way to predict how much C stack is left, because that
depends on the OS and how much is consumed by the hosting C
program or by called C functions. Basically, any C function that
can be called from Lua and calls back into Lua could potentially
be used to overflow the stack, given the right circumstances.
--Mike
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