ksplice-create creates a set of Ksplice kernel modules that, when loaded,
will apply a user-specified source code patch to the running binary kernel.
Before you use ksplice-create on a patch, you should confirm that the
desired source code change does not make any semantic changes to kernel data
structures---that is, changes that would require existing instances of kernel
data structures to be transformed (e.g., a patch that adds a field to a global
data structure would require the existing data structures to change). If you
use Ksplice on a patch that changes data structure semantics, Ksplice will not
detect the problem and you could experience kernel problems as a result.
The to-be-applied source code patch can be specified by providing a patch(1)
file (--patch=PATCH_FILE) or by providing a file extension
If a file extension is specified, then the desired source code patch will be
determined by comparing all of the files in the KERNEL_SOURCE directory tree
whose names end with the extra extension EXTENSION against the corresponding
files without the extra extension. Only the new files containing the extra
extension in their filenames should be modified.
Here is an example of using a file extension to specify a patch:
$ cp KERNEL_SOURCE/kernel/sys.c KERNEL_SOURCE/kernel/sys.c.prctl_fixed
[edit sys.c.prctl_fixed to include the desired changes]
$ ksplice-create --diffext=.prctl_fixed KERNEL_SOURCE
KERNEL_SOURCE must be a directory containing the to-be-updated kernel's
original source code. If your Linux distribution applies patches to the Linux
kernel during the kernel build process, then those patches must be applied to
the KERNEL_SOURCE directory before invoking ksplice-create on that
directory. ksplice-create will not modify the source code in the
KERNEL_SOURCE directory tree, but it will perform a kernel build in that
ORIG_CONFIG can be used to specify the directory containing the
to-be-updated kernel's original .config file and original System.map file
(the files should have exactly those names). ORIG_CONFIG defaults to
The default gcc(1) compiler and as(1) assembler on the system should be as
close to the compiler and assembler originally used to build the running kernel
as possible. If the current compiler and linker are too different from the
original compiler and linker, ksplice-apply will abort when applying the
ksplice-create outputs a tar(1) file, compressed with gzip(1),
containing the desired Ksplice update modules. This tarball will be created in
the current directory, and it can be manipulated using the other Ksplice
utilities, such as ksplice-apply.
The first time that ksplice-create is invoked on a KERNEL_SOURCE
directory, it must build that kernel from scratch, which is much slower than
the rest of the update-creation process. --prebuild can be used to perform
this initial kernel build without providing a source code patch.
In order to patch a function that has previously been patched by Ksplice, the
user needs to ensure that the KERNEL_SOURCE directory provided to Ksplice
contains the source for the currently running kernel, including any patches
that have previously been applied by Ksplice.
Builds a Ksplice update out of the given patch(1) file PATCH_FILE.
Builds a Ksplice update using the modified source files with names ending in
EXTENSION. The patch will be determined by comparing all of the files in the
KERNEL_SOURCE directory tree whose names end with the extra extension
EXTENSION against the corresponding files without the extra extension.
Builds a Ksplice update using the commit COMMIT in the Git working tree
KERNEL_SOURCE. The original state corresponding to the running kernel is
remembered in the Git ref refs/ksplice/pre, which will be created from the
current HEAD if it does not yet exist (and can be changed using the
--series option). Therefore, the source code change to be applied
corresponds to the output of git diff ksplice/preCOMMIT.
Compiles the original source code that will be needed to build future Ksplice
updates. If any Ksplice updates have previously been built in the
KERNEL_SOURCE tree, the source files in the tree are reverted to their
Specifies that the current state of the KERNEL_SOURCE tree should be used as
the original source that corresponds to the running kernel. If a Ksplice update
has recently been built in the KERNEL_SOURCE tree, this option specifies that
the Ksplice update being built should be applied after the previous update in
series. This option can be used with --prebuild to forget the previous
original state and perform no other action.
For a patch that includes changes to kernel modules, in addition to building a
hot update that can be applied to the running kernel, this option will cause
ksplice-create to generate a set of new modules based on the updated source
code. These modules can be used to replace the kernel modules stored on disk,
where they can later be loaded normally after part of the hot update has been
applied using ksplice-apply(1) --partial.
Causes ksplice-create to print debugging messages about its progress. Using
multiple -v options increases the verbosity. The maximum is 2.
Specifies the number of jobs to run simultaneously while performing kernel
builds. ksplice-create also honors the environment variable
Can be used to pass options to patch(1). If this option is NOT specified, then
-p1 is passed to patch. If this option is specified, then only the
specified options will be passed to patch. This option can be repeated in
order to pass multiple options to patch. This option is ignored when the
to-be-applied source code patch is specified using --diffext.
Specifies the unique value that will be used as the identifier of the
Ksplice update. This identifier will, for example, appear in the name
of the update tarball. By default, a random 8-character ID will be