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Subject[PATCH] livepatch: Remove not longer valid limitations from the documentation
Semantic changes are possible since the commit d83a7cb375eec21f04
("livepatch: change to a per-task consistency model").

Also data structures can be patched since the commit 439e7271dc2b63de37
("livepatch: introduce shadow variable API").

It is a high time we removed these limitations from the documentation.

Signed-off-by: Petr Mladek <>
I have found this when working on v12 of the atomic replace. It looks
like a no-brainer and does not conflict with the patchset, so ... ;-)

Documentation/livepatch/livepatch.txt | 24 ------------------------
1 file changed, 24 deletions(-)

diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt
index 1ae2de758c08..2d7ed09dbd59 100644
--- a/Documentation/livepatch/livepatch.txt
+++ b/Documentation/livepatch/livepatch.txt
@@ -429,30 +429,6 @@ See Documentation/ABI/testing/sysfs-kernel-livepatch for more details.

The current Livepatch implementation has several limitations:

- + The patch must not change the semantic of the patched functions.
- The current implementation guarantees only that either the old
- or the new function is called. The functions are patched one
- by one. It means that the patch must _not_ change the semantic
- of the function.
- + Data structures can not be patched.
- There is no support to version data structures or anyhow migrate
- one structure into another. Also the simple consistency model does
- not allow to switch more functions atomically.
- Once there is more complex consistency mode, it will be possible to
- use some workarounds. For example, it will be possible to use a hole
- for a new member because the data structure is aligned. Or it will
- be possible to use an existing member for something else.
- There are no plans to add more generic support for modified structures
- at the moment.
+ Only functions that can be traced could be patched.

Livepatch is based on the dynamic ftrace. In particular, functions
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