L4android mlock on vectors page causes unresolvable page fault

Matthias Petschick matthias at sec.t-labs.tu-berlin.de
Mon Apr 8 15:35:53 CEST 2013

On 04/08/2013 01:50 AM, Matthias Petschick wrote:
> I can't test it right now but without looking too deep, I predict that
> it will work because mlockall calls
> do_mlock_pages(0, TASK_SIZE, 1);
> and TASK_SIZE is 0xbfc00000 for arch/l4, hence the vectors page should
> not be touched by it. Will nevertheless give it a shot tomorrow in case
> I missed something.

Yes, works as predicted.
In case of lvm, the problem can of course be averted by either
blacklisting the vectors page or configuring it to use mlockall. I can't
say if the way mlock ungracefully handles attempts to lock the vectors
page has any further, not directly obvious implications though.

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