Re: [Tails-dev] Shutdown stopped working in nightly experime…

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Author: intrigeri
Date:  
To: The Tails public development discussion list
Subject: Re: [Tails-dev] Shutdown stopped working in nightly experimental?
winterfairy@??? wrote (27 Nov 2013 14:10:51 GMT) :
> When it reboots even though I selected shutdown, it actually does not
> reboot properly. It reboot early in the memory erasing procedure (possibly
> in the beginning) and leaves the memory unerased.


I'll try to reproduce this (but IIRC on the ThinkPenguin Royal, it did
reboot cleanly). Worst case, this will be added to the known issues of
the next release, but it would be great if this could be investigated
further.

> This makes me believe the memory erasing acts badly with this kernel
> version and hardware combination, possibly writing some data somewhere it
> shouldn't had, causing the kernel or hardware to force a reboot. And that
> it worked with previous kernel versions on this hardware by pure luck.


My understanding is that sdmem shouldn't be allowed to write to places
it shouldn't. Changes in the OOM area, perhaps?

> I want to look deeper into this, but I cannot find where the actual memory
> erasing code is (where sdmem is started?)? Only where the kexec bits are.
> Where is it?


You want to look at
https://tails.boum.org/contribute/design/memory_erasure/ and
/usr/share/initramfs-tools/scripts/init-premount/sdmem

Cheers,
--
intrigeri
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