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authorPetr Mladek <pmladek@suse.com>2018-05-23 09:47:42 +0200
committerJiri Kosina <jkosina@suse.cz>2018-05-24 15:37:57 +0200
commita48c7709fe42712e86d2d68e1c9c4d2ce14c6a16 (patch)
treedee5ede0e4ef058f780a4f6429bee8a33b9b19b2 /Documentation/livepatch
parent41e3bef52e42c03cb7234f2d8419352478c92926 (diff)
downloadlwn-a48c7709fe42712e86d2d68e1c9c4d2ce14c6a16.tar.gz
lwn-a48c7709fe42712e86d2d68e1c9c4d2ce14c6a16.zip
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 <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'Documentation/livepatch')
-rw-r--r--Documentation/livepatch/livepatch.txt24
1 files changed, 0 insertions, 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