[SRU][Bionic][Cosmic][PATCH 0/1] powerpc/livepatch: Implement reliable stack tracing for the consistency model

[Joseph Salisbury]

BugLink: http://bugs.launchpad.net/bugs/1771844

== SRU Justification ==
Livepatch has a consistency model which is a hybrid of kGraft and kpatch: 
it uses kGraft's per-task consistency and syscall barrier switching 
combined with kpatch's stack trace switching. The current approach is 
stack checking of sleeping tasks. If no affected functions are on the 
stack of a given task, the task is patched. In most cases this will patch 
most or all of the tasks on the first try. Otherwise, it'll keep trying 
periodically. This patch implements the reliable stack tracing for 
consistency model a.k.a HAVE_RELIABLE_STACKTRACE.

This will help in switching livepatching implementation to basic per-task 
consistency model. It is the foundation, which will help us enable 
security patches changing function or data semantics. This is the biggest 
remaining piece needed on ppc64le to make livepatch more generally useful.

== Fix ==
df78d3f61480 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model")

== Regression Potential ==
Low. Limited to powerpc.

== Test Case ==
A test kernel was built with this patch and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.


Torsten Duwe (1):
  powerpc/livepatch: Implement reliable stack tracing for the
    consistency model

 arch/powerpc/Kconfig             |   1 +
 arch/powerpc/kernel/stacktrace.c | 119 ++++++++++++++++++++++++++++++-
 2 files changed, 119 insertions(+), 1 deletion(-)

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2.17.0