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Michael Ackermann via Tinycc-devel <[email protected]> wrote:
> Now, and this could be relevant to tinycc-devel, dont' ask me how i arrived at
> this in desperate need for some workaround again, see the following patch;
> when i've added some NOPs into empty function dummies the kernel panics
> in conjunction with the re-implemented random_scrandom.c/scrandom.c vanished:

this doesn't fix the bug, some issue on the stack remains

> 
> /*
>  * linux-2.4.37/drivers/char/random_scrandom.c to replace random.c
>  * 
> https://codeberg.org/aggi/linux-tcc/commit/139f6824b57fb186ab8fcdb624f801194e1dda15
>  */
> void add_keyboard_randomness(unsigned char scancode) {
> +
> +       int nop = 0;
> }
> 
> Which raises a suspicion, maybe tinycc does some dead-code elimination

no

> adding some NOP into empty function dummies affects symbols linked into 
> kernel?

they're not NOPs, adding a variable there affects the stack
adding a "int nop = 0;" is misleading - this changes the stack pointer compared 
to what it would have been

> I haven't the slightest clue again, but i could confirm with some certainty

if you want to learn about this, feel free to use some reverse-engineering 
tools for your aid - see attachments
just looking at the C code isn't going to give you the information that you 
require for learning about this

> Anyway, i've deployed the tinycc-driven distribution into production as
> my main development host regardless, and entire userspace seems sufficiently

interesting, please keep us updated

> stable (mutt, irc, lighttpd, ssh, nfs, tor-proxy, can't test all 500 builds
> individually, it's up and running for days and weeks).
> Which means, other than the somewhat annoying linux-tcc kernel bugs confirmed
> for being related to compilation/linking with tinycc the whole thing is
> approaching a release-tag made for upload.

good

> Otherwise i've not made any progress when contacting various employers,
> universities etc. which complicates the situation.

I'm wondering how you phrase those requests, perhaps you should package what 
you're selling a little differently according to your audience (i.e. someone 
who d.g.a.f about that apart from surviving another day at work)

--

more details on attachments:
- the DWARF format is more usable than STABS with radare2 and rizin
- it seems like the tcc DWARF output is not quite there yet for r2 - those 
source code annotations are misleading
- tcc has an 'optimize' flag, which has an effect when its value is greater 
than 0 - i.e. -O0 disables them, -Os, -O1, -O2 lead to the same effect
- feel free to confirm the lack of "dead code elimination" by disabling the 
debug output option and enabling the tiny bit of optimization that is available
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