SRU request submitted:
https://lists.ubuntu.com/archives/kernel-team/2018-May/092679.html
** Description changed:
- == Comment: #0 - Kamalesh Babulal - 2018-05-15 09:37:52 ==
- 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.
+ == 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.
+ 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.
+
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=df78d3f6148092d33a9a24c7a9cfac
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https://bugs.launchpad.net/bugs/1771844
Title:
powerpc/livepatch: Implement reliable stack tracing for the
consistency model
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