From: Jeff King <peff@peff.net>
Date: Sun, 20 Apr 2014 01:35:00 GMT
Subject: Re: [PATCH 1/6] run_external_diff: use an argv_array for the command line
Message-ID: <20140420013500.GB10531@sigill.intra.peff.net>
In-Reply-To: <CAA6TxYu=AX_RWQq4gr7cv6ZppPerRw30NY_Wbi1r8qEBma7Ctg@mail.gmail.com>

On Sun, Apr 20, 2014 at 02:09:49AM +0400, Max L wrote:

> One more note: at this moment the problem is slightly deeper. This
> array is next passed to the execvp function, which now falls with
> EFAULT on two my machines (both faced this problem after upgrading to
> ubuntu 14.04, everything 'worked' fine before, looks like now execvp
> checks input more strictly). This leads to non-working 'git difftool'.

Interesting. We're overwriting whatever is after spawn_arg on the stack,
so I'd expect the fork/exec to work, but the function to complain while
popping the stack frame (though I couldn't get it to do so). I wonder if
some kind of stack protection is kicking in, and the NULL doesn't get
written or something. Either way, we should definitely address it.

-Peff