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.
220 all module options to built in (=y) options.
222 "make kvmconfig" Enable additional options for kvm guest kernel support.
224 "make xenconfig" Enable additional options for xen dom0 guest kernel
227 "make tinyconfig" Configure the tiniest possible kernel.
229 You can find more information on using the Linux kernel config tools
230 in Documentation/kbuild/kconfig.rst.
232 - NOTES on ``make config``:
234 - Having unnecessary drivers will make the kernel bigger, and can
238 - A kernel with math-emulation compiled in will still use the
240 never get used in that case. The kernel will be slightly larger,
244 - The "kernel hacking" configuration details usually result in a
245 bigger or slower kernel (or both), and can even make the kernel
247 break bad code to find kernel problems (kmalloc()). Thus you
251 Compiling the kernel
252 --------------------
254 - Make sure you have at least gcc 4.6 available.
257 Please note that you can still run a.out user programs with this kernel.
259 - Do a ``make`` to create a compressed kernel image. It is also
261 kernel makefiles, but you may want to check your particular lilo setup first.
264 build should require that. Don't take the name of root in vain.
266 - If you configured any of the parts of the kernel as ``modules``, you
269 - Verbose kernel compile/build output:
271 Normally, the kernel build system runs in a fairly quiet mode (but not
272 totally silent). However, sometimes you or other kernel developers need
282 - Keep a backup kernel handy in case something goes wrong. This is
285 backup of the modules corresponding to that kernel, as well. If you
286 are installing a new kernel with the same version number as your
287 working kernel, make a backup of your modules directory before you
290 Alternatively, before compiling, use the kernel config option
291 "LOCALVERSION" to append a unique suffix to the regular kernel version.
292 LOCALVERSION can be set in the "General Setup" menu.
294 - In order to boot your new kernel, you'll need to copy the kernel
296 to the place where your regular bootable kernel is found.
298 - Booting a kernel directly from a floppy without the assistance of a
302 uses the kernel image as specified in the file /etc/lilo.conf. The
303 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
304 /boot/bzImage. To use the new kernel, save a copy of the old image
307 the new kernel image.
311 old kernel image (say, /vmlinux.old) in case the new one does not
318 ramdisk size, etc. in the kernel image, use the ``rdev`` program (or
320 recompile the kernel to change these parameters.
322 - Reboot with the new kernel and enjoy.
325 -----------------------
327 - If you have problems that seem to be due to kernel bugs, please check
329 with the part of the kernel that you are having trouble with. If there
331 them to me (torvalds@linux-foundation.org), and possibly to any other
332 relevant mailing-list or to the newsgroup.
334 - In all bug-reports, *please* tell what kernel you are talking about,
339 - If the bug results in a message like::
341 unable to handle kernel paging request at address C0000010
350 or similar kernel debugging information on your screen or in your
354 important: it tells something about why the kernel dumped code (in
355 the above example, it's due to a bad kernel pointer). More information
356 on making sense of the dump is in Documentation/admin-guide/bug-hunting.rst
358 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
362 https://www.kernel.org/pub/linux/utils/kernel/ksymoops/ .
365 - In debugging dumps like the above, it helps enormously if you can
368 kernel setup. What you should do is take the hex value from the EIP
369 line (ignore the ``0010:``), and look it up in the kernel namelist to
370 see which kernel function contains the offending address.
372 To find out the kernel function name, you'll need to find the system
373 binary associated with the kernel that exhibited the symptom. This is
375 the EIP from the kernel crash, do::
379 This will give you a list of kernel addresses sorted in ascending
381 offending address. Note that the address given by the kernel
383 function addresses (in fact, that is very unlikely), so you can't
385 point of each kernel function, so by looking for the function that
388 you want. In fact, it may be a good idea to include a bit of
389 "context" in your problem report, giving a few lines around the
392 If you for some reason cannot do the above (you have a pre-compiled
393 kernel image or similar), telling me as much about your setup as
394 possible will help. Please read the :ref:`admin-guide/reporting-bugs.rst <reportingbugs>`
397 - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
399 kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make
402 After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``.
407 gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly)
408 disregards the starting offset for which the kernel is compiled.