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Merge pull request #491 from jpoimboe/readme-oot 

README updates: patch out-of-tree modules and remove some obsolete info
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Seth Jennings 2015-06-25 00:02:06 -04:00
parent de22702b21 99be07a372
commit 667692639e
1 changed files with 7 additions and 16 deletions
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README.md
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@ -425,7 +425,7 @@ Frequently Asked Questions
**Q. What's the relationship between kpatch and the upstream Linux live kernel **Q. What's the relationship between kpatch and the upstream Linux live kernel
patching component (livepatch)?** patching component (livepatch)?**
Starting with Linux 4.0, the Linux kernel will have livepatch, which is a new Starting with Linux 4.0, the Linux kernel has livepatch, which is a new
converged live kernel patching framework. Livepatch is similar in converged live kernel patching framework. Livepatch is similar in
functionality to the kpatch core module, though it doesn't yet have all the functionality to the kpatch core module, though it doesn't yet have all the
features that kpatch does. features that kpatch does.
@ -517,12 +517,6 @@ We hope to make the following changes to other projects:
- kernel: - kernel:
- ftrace improvements to close any windows that would allow a patch to - ftrace improvements to close any windows that would allow a patch to
be inadvertently disabled be inadvertently disabled
- hot patch taint flag
- possibly the kpatch core module itself
- crash:
- point it to where the patch modules and corresponding debug symbols
live on the file system
**Q: Is it possible to register a function that gets called atomically with **Q: Is it possible to register a function that gets called atomically with
`stop_machine` when the patch module loads and unloads?** `stop_machine` when the patch module loads and unloads?**
@ -555,15 +549,6 @@ There could be a variety of reasons for this, such as:
- The compiler decided to inline a changed function, resulting in the outer - The compiler decided to inline a changed function, resulting in the outer
function getting recompiled. This is common in the case where the inner function getting recompiled. This is common in the case where the inner
function is static and is only called once. function is static and is only called once.
- The function uses a WARN() or WARN_ON() macro. These macros embed the source
code line number (`__LINE__`) into an instruction. If a function was changed
higher up in the file, it will affect the line numbers for all subsequent
WARN calls in the file, resulting in recompilation of their functions. If
this happens to you, you can usually just ignore it, as patching a few extra
functions isn't typically a problem. If it becomes a problem for whatever
reason, you can change the source patch to redefine the WARN macro for the
affected files, such that it hard codes the old line number instead of using
`__LINE__`, for example.
**Q. How do I patch a function which is always on the stack of at least one **Q. How do I patch a function which is always on the stack of at least one
task, such as schedule(), sys_poll(), sys_select(), sys_read(), task, such as schedule(), sys_poll(), sys_select(), sys_read(),
@ -578,6 +563,12 @@ sys_nanosleep(), etc?**
- Yes. - Yes.
**Q. Can you patch out-of-tree modules?**
- Yes, though it's currently a bit of a manual process. See this
[message](https://www.redhat.com/archives/kpatch/2015-June/msg00004.html) on
the kpatch mailing list for more information.
Get involved Get involved
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