Re: [RFC PATCH v1.9 00/14] livepatch: hybrid consistency model

From: Miroslav Benes
Date: Fri Apr 01 2016 - 09:35:14 EST



> - actually test it

I did slightly and it partially worked and partially it did not.

When I applied sample livepatch module, /proc/cmdline was patched and when
I called 'cat /proc/cmdline' I got the correct livepatched message. So far
so good. But the patching itself never finished because of many processes
with unreliable stacks. It almost looked like every sleeping process was
reported. I haven't debugged that yet.

Second, I have a simple test case. Kthread which sleeps in to-be-patched
function foo() for a while and then it sleeps somewhere else and that in a
loop. After live patch application the kthread is reported to have
unreliable stack and it is not migrated. The good thing is that also the
function foo() from the old universe is called and thus the consistency
model works.

So I guess there is some problem in a stack checking...

Miroslav