Re: [LuaJIT] Segmentation Faults When GC'ing

[Mike Pall <mikelu-1204@...>]

Alex wrote:
> Hi again. I'm having issues closing my server program. It's causing a
> segfault in the GC with the following backtrace:
> 
> #0  0x66dcaee1 in lj_alloc_free (msp=0x2b0008, ptr=<optimized out>) at
> lj_alloc.c:1268

This looks like a buffer overrun, which corrupts the free lists of
the memory allocator. One possible cause is misuse of the FFI
(0-based vs. 1-based array mixup).

First, try using the system memory allcator, which often has some
extra debug options.

Or try Valgrind, except ...

> Win7 x64 (but compiled with -m32), compiled with asserts, debug info, and
> gdb jit stuff.

... Valgrind doesn't run on Windows.

And in fact the GDB JIT stuff only works on ELF targets, so you
might as well disable it. But I don't think it should cause a
crash, except when GDB tries to access the JIT symbols. The bogus
notifications from GDB in your other message indicate it doesn't
handle that very well.

--Mike