misbehaving system halting work

Karl gmkarl at gmail.com
Fri Feb 26 11:14:50 PST 2021

Hey coderman,

The structure you link to is local to only that static function.  It
doesn't share the reference outside the function, to lead to the corruption
you express concern around.  The class also has a member variable for use
in a more ongoing way.

Maybe it would be good to use an instance of the class in that static
function to be more organised, though, or something.

I mentioned the issue on the chat and got a couple recommendations for
antivirus software.  I'm thinking if I could use an android emulator to
bundle the issue up so it reproduces, I'm thinking it might help for giving
something to an antivirus vendor.

I'm not sure.  Sometimes I struggle to continue with projects and there are
extensive delays (a number of years now for my volk pull request).  This
looks likely to be one of those times; we'll find out.

On Fri, Feb 26, 2021, 12:14 PM coderman <coderman at protonmail.com> wrote:

> Hash: SHA512
> hello Karl!
> i haven't had time to dig into this much, but one thing stuck out to me
> in how you're using the FTDI content and functions.
> here you initialize the ftdi_content, but are using a local structure
> variable:
> https://github.com/xloem/brainflow/blob/ecd1049f3a4146bd24a0b21f50b5267eb1d6190d/src/utils/libftdi_serial.cpp#L40
> once you return from  LibFTDISerial::is_libftdi () function, the
> ftdi_context will be destroyed.
> you'll notice that this context must live as long as the process, otherwise
> references to it will become invalid, leading to stack / heap corruption.
> for example, this usage calls from main(), where the ftdi_context will
> exist as long as the program is running:
> https://github.com/punyal/Contiki_3-IPsec/blob/93130cd1123f362594e915283dbf7f2783eeea43/platform/mulle/tools/scan_ftdi/scan_ftdi.c#L17
> you could solve this by declaring a static (global) ftdi_context, however,
>  this entails locking / concurrency concerns.
> i hope this helps. perhaps later this weekend i dig in depth into your
> problems.
> best regards,
> c3N1ZXItZnByQG5vdGF0aW9ucy5vcGVucGdwLmZpZnRoaG9yc2VtYW4ubmV0NDFD
> DJSNAP4/21OaXu96TS2w7kZGQhurSOQilGQ+ZA4g6TllSIKUVgEAzbeQ7/hmf3Nw
> eZfqr5al/5d5LZF3bFcfKqJ1E1fmh8s=
> =EkrV
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