Livepatch is based on the dynamic ftrace,
so functions that can be traced could be patched.
Inlined functions aren't traced by the function tracer.
Even if CONFIG_OPTIMIZE_INLINING is set, they aren't traced
because of marked with "notrace". We can see it from the commit
45959ee7aa6 ("ftrace: Do not function trace inlined functions")
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Miroslav Benes <mbenes@xxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
---
Documentation/livepatch/livepatch.txt | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt
index ecdb181..65f784a 100644
--- a/Documentation/livepatch/livepatch.txt
+++ b/Documentation/livepatch/livepatch.txt
@@ -475,6 +475,9 @@ The current Livepatch implementation has several limitations:
potential mistake is prevented by marking the problematic functions
by "notrace".
+ Besides, inlined functions could not be patched. Because they are
+ not traced by the function tracer and even if CONFIG_OPTIMIZE_INLINING
+ is set, they are marked with "notrace".
+ Livepatch works reliably only when the dynamic ftrace is located at
--
2.7.4
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