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 <[email protected]>
---
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
--
2.13.6
s/Remove not longer/Remove no longer/
On Wed, 23 May 2018, Petr Mladek wrote:
> 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 <[email protected]>
Acked-by: Miroslav Benes <[email protected]>
M
On Wed, May 23, 2018 at 03:07:05PM +0200, Miroslav Benes wrote:
>
> s/Remove not longer/Remove no longer/
>
> On Wed, 23 May 2018, Petr Mladek wrote:
>
> > 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 <[email protected]>
>
> Acked-by: Miroslav Benes <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
--
Josh
On Wed, 23 May 2018, Petr Mladek wrote:
> 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 <[email protected]>
> ---
> 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 ... ;-)
Applied, thanks.
--
Jiri Kosina
SUSE Labs