ksplice-create - Create a set of kernel modules for a rebootless kernel
ksplice-create [OPTIONS] --patch=PATCH_FILE KERNEL_SOURCE
ksplice-create [OPTIONS] --diffext=EXTENSION KERNEL_SOURCE
ksplice-create [OPTIONS] --git=COMMIT KERNEL_SOURCE
ksplice-create [OPTIONS] --prebuild KERNEL_SOURCE
ksplice-create creates a set of Ksplice kernel modules that, when
loaded, will apply a user-specified source code patch to the running
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
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 directory tree.
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 update.
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
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
Builds a Ksplice update out of the given patch(1) 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/pre COMMIT.
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 original state.
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)
Causes ksplice-create to print debugging messages about its
progress. Using multiple -v options increases the verbosity.
The maximum is 2.
-j JOBS, --jobs=JOBS
Specifies the number of jobs to run simultaneously while
performing kernel builds. ksplice-create also honors the
environment variable CONCURRENCY_LEVEL.
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.
--id=ID 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 generated.
ksplice-apply(8), ksplice-view(8), ksplice-undo(8)
Please report bugs to <email@example.com>.
Jeff Arnold, Anders Kaseorg, and Tim Abbott
Copyright (C) 2007-2009 Ksplice, Inc.
This is free software and documentation. You can redistribute and/or
modify it under the terms of the GNU General Public License, version 2.