ZyX wrote:

> While searching for the bug in my extended-funcref branch I found that
> *in this branch* it is possible to access freed memory: variable
> cleared by vars_clear may contain reference to the variable already
> freed by vim_free(SCRIPT_SV(i)).
> 
> Almost minimal example of environment that is enough for reproducing
> the bug is attached. Note that only build with EXITFREE defined
> (normally development build) is subject to this kind of error. To see
> this error run under valgrind
> 
>     vim -u ../vimrc -s efref-valgrind.in
> 
> while being in test/ subdirectory found in the archive. This error
> happens for both my branch and upstream, but I was thinking it was my
> failure because I did not have development version of upstream
> compiled.
> 
> The following patch fixes the problem for me (main idea is that you
> first clear all variables and only then do actual freeing).
> 
> Note that it may make sense to defer the second cycle (and hence
> ga_clear() call) until garbage_collect() call (in case reference to
> script-local scope is saved to a list/dictionary that then became
> unreferenced), but I am not sure.

Thanks for finding this and providing a solution.  I'll have to think
about whether there is still a way this may fail.


-- 
Emacs is a nice OS - but it lacks a good text editor.
That's why I am using Vim.  --Anonymous

 /// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net   \\\
///        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\  an exciting new programming language -- http://www.Zimbu.org        ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///

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