Lines Matching +full:in +full:- +full:kernel
3 Linux kernel release 5.x <http://kernel.org/>
8 kernel, and what to do if something goes wrong.
11 --------------
14 Linus Torvalds with assistance from a loosely-knit team of hackers across
17 It has all the features you would expect in a modern fully-fledged Unix,
19 loading, shared copy-on-write executables, proper memory management,
22 It is distributed under the GNU General Public License v2 - see the
26 -----------------------------
28 Although originally developed first for 32-bit x86-based PCs (386 or higher),
31 IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64 Xtensa, and
34 Linux is easily portable to most general-purpose 32- or 64-bit architectures
39 Linux has also been ported to itself. You can now run the kernel as a
40 userspace application - this is called UserMode Linux (UML).
43 -------------
45 - There is a lot of documentation available both in electronic form on
46 the Internet and in books, both Linux-specific and pertaining to
52 - There are various README files in the Documentation/ subdirectory:
53 these typically contain kernel-specific installation notes for some
57 your kernel.
59 Installing the kernel source
60 ----------------------------
62 - If you install the full sources, put the kernel tarball in a
66 xz -cd linux-5.x.tar.xz | tar xvf -
68 Replace "X" with the version number of the latest kernel.
71 incomplete) set of kernel headers that are used by the library header
73 whatever the kernel-du-jour happens to be.
75 - You can also upgrade between 5.x releases by patching. Patches are
76 distributed in the xz format. To install by patching, get all the
77 newer patch files, enter the top level directory of the kernel source
78 (linux-5.x) and execute::
80 xz -cd ../patch-5.x.xz | patch -p1
84 the backup files (some-file-name~ or some-file-name.orig), and make sure
85 that there are no failed patches (some-file-name# or some-file-name.rej).
89 (also known as the -stable kernels) are not incremental but instead apply
90 directly to the base 5.x kernel. For example, if your base kernel is 5.0
92 and 5.0.2 patches. Similarly, if you are running kernel version 5.0.2 and
94 patch -R) **before** applying the 5.0.3 patch. You can read more on this in
95 :ref:`Documentation/process/applying-patches.rst <applying_patches>`.
97 Alternatively, the script patch-kernel can be used to automate this
98 process. It determines the current kernel version and applies any
101 linux/scripts/patch-kernel linux
103 The first argument in the command above is the location of the
104 kernel source. Patches are applied from the current directory, but
107 - Make sure you have no stale .o files and dependencies lying around::
115 ---------------------
117 Compiling and running the 5.x kernels requires up-to-date
126 Build directory for the kernel
127 ------------------------------
129 When compiling the kernel, all output files will per default be
130 stored together with the kernel source code.
135 kernel source code: /usr/src/linux-5.x
136 build directory: /home/name/build/kernel
138 To configure and build the kernel, use::
140 cd /usr/src/linux-5.x
141 make O=/home/name/build/kernel menuconfig
142 make O=/home/name/build/kernel
143 sudo make O=/home/name/build/kernel modules_install install
148 Configuring the kernel
149 ----------------------
152 version. New configuration options are added in each release, and
158 - Alternative configuration commands are::
210 and pass it in as a LSMOD parameter.
212 Also, you can preserve modules in certain folders
213 or kconfig files by specifying their paths in
226 all module options to built in (=y) options. You can
229 "make kvm_guest.config" Enable additional options for kvm guest kernel
232 "make xen.config" Enable additional options for xen dom0 guest kernel
235 "make tinyconfig" Configure the tiniest possible kernel.
237 You can find more information on using the Linux kernel config tools
238 in Documentation/kbuild/kconfig.rst.
240 - NOTES on ``make config``:
242 - Having unnecessary drivers will make the kernel bigger, and can
246 - A kernel with math-emulation compiled in will still use the
248 never get used in that case. The kernel will be slightly larger,
252 - The "kernel hacking" configuration details usually result in a
253 bigger or slower kernel (or both), and can even make the kernel
255 break bad code to find kernel problems (kmalloc()). Thus you
259 Compiling the kernel
260 --------------------
262 - Make sure you have at least gcc 5.1 available.
265 Please note that you can still run a.out user programs with this kernel.
267 - Do a ``make`` to create a compressed kernel image. It is also
269 kernel makefiles, but you may want to check your particular lilo setup first.
272 build should require that. Don't take the name of root in vain.
274 - If you configured any of the parts of the kernel as ``modules``, you
277 - Verbose kernel compile/build output:
279 Normally, the kernel build system runs in a fairly quiet mode (but not
280 totally silent). However, sometimes you or other kernel developers need
290 - Keep a backup kernel handy in case something goes wrong. This is
293 backup of the modules corresponding to that kernel, as well. If you
294 are installing a new kernel with the same version number as your
295 working kernel, make a backup of your modules directory before you
298 Alternatively, before compiling, use the kernel config option
299 "LOCALVERSION" to append a unique suffix to the regular kernel version.
300 LOCALVERSION can be set in the "General Setup" menu.
302 - In order to boot your new kernel, you'll need to copy the kernel
304 to the place where your regular bootable kernel is found.
306 - Booting a kernel directly from a floppy without the assistance of a
310 uses the kernel image as specified in the file /etc/lilo.conf. The
311 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
312 /boot/bzImage. To use the new kernel, save a copy of the old image
315 the new kernel image.
319 old kernel image (say, /vmlinux.old) in case the new one does not
326 etc. in the kernel image, use your bootloader's boot options
327 where appropriate. No need to recompile the kernel to change
330 - Reboot with the new kernel and enjoy.
333 -----------------------
335 - If you have problems that seem to be due to kernel bugs, please check
337 with the part of the kernel that you are having trouble with. If there
339 them to me (torvalds@linux-foundation.org), and possibly to any other
340 relevant mailing-list or to the newsgroup.
342 - In all bug-reports, *please* tell what kernel you are talking about,
347 - If the bug results in a message like::
349 unable to handle kernel paging request at address C0000010
358 or similar kernel debugging information on your screen or in your
362 important: it tells something about why the kernel dumped code (in
363 the above example, it's due to a bad kernel pointer). More information
364 on making sense of the dump is in Documentation/admin-guide/bug-hunting.rst
366 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
370 https://www.kernel.org/pub/linux/utils/kernel/ksymoops/ .
373 - In debugging dumps like the above, it helps enormously if you can
376 kernel setup. What you should do is take the hex value from the EIP
377 line (ignore the ``0010:``), and look it up in the kernel namelist to
378 see which kernel function contains the offending address.
380 To find out the kernel function name, you'll need to find the system
381 binary associated with the kernel that exhibited the symptom. This is
383 the EIP from the kernel crash, do::
387 This will give you a list of kernel addresses sorted in ascending
389 offending address. Note that the address given by the kernel
391 function addresses (in fact, that is very unlikely), so you can't
393 point of each kernel function, so by looking for the function that
396 you want. In fact, it may be a good idea to include a bit of
397 "context" in your problem report, giving a few lines around the
400 If you for some reason cannot do the above (you have a pre-compiled
401 kernel image or similar), telling me as much about your setup as
403 'Documentation/admin-guide/reporting-issues.rst' for details.
405 - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
407 kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make
410 After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``.
415 gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly)
416 disregards the starting offset for which the kernel is compiled.