| 1 | ␉Linux kernel release 2.6.xx <http://kernel.org/>␊ |
| 2 | ␊ |
| 3 | These are the release notes for Linux version 2.6. Read them carefully,␊ |
| 4 | as they tell you what this is all about, explain how to install the␊ |
| 5 | kernel, and what to do if something goes wrong. ␊ |
| 6 | ␊ |
| 7 | WHAT IS LINUX?␊ |
| 8 | ␊ |
| 9 | Linux is a clone of the operating system Unix, written from scratch by␊ |
| 10 | Linus Torvalds with assistance from a loosely-knit team of hackers across␊ |
| 11 | the Net. It aims towards POSIX and Single UNIX Specification compliance.␊ |
| 12 | ␊ |
| 13 | It has all the features you would expect in a modern fully-fledged Unix,␊ |
| 14 | including true multitasking, virtual memory, shared libraries, demand␊ |
| 15 | loading, shared copy-on-write executables, proper memory management,␊ |
| 16 | and multistack networking including IPv4 and IPv6.␊ |
| 17 | ␊ |
| 18 | It is distributed under the GNU General Public License - see the␊ |
| 19 | accompanying COPYING file for more details. ␊ |
| 20 | ␊ |
| 21 | ON WHAT HARDWARE DOES IT RUN?␊ |
| 22 | ␊ |
| 23 | Although originally developed first for 32-bit x86-based PCs (386 or higher),␊ |
| 24 | today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and␊ |
| 25 | UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,␊ |
| 26 | IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,␊ |
| 27 | Xtensa, AVR32 and Renesas M32R architectures.␊ |
| 28 | ␊ |
| 29 | Linux is easily portable to most general-purpose 32- or 64-bit architectures␊ |
| 30 | as long as they have a paged memory management unit (PMMU) and a port of the␊ |
| 31 | GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has␊ |
| 32 | also been ported to a number of architectures without a PMMU, although␊ |
| 33 | functionality is then obviously somewhat limited.␊ |
| 34 | Linux has also been ported to itself. You can now run the kernel as a␊ |
| 35 | userspace application - this is called UserMode Linux (UML).␊ |
| 36 | ␊ |
| 37 | DOCUMENTATION:␊ |
| 38 | ␊ |
| 39 | - There is a lot of documentation available both in electronic form on␊ |
| 40 | the Internet and in books, both Linux-specific and pertaining to␊ |
| 41 | general UNIX questions. I'd recommend looking into the documentation␊ |
| 42 | subdirectories on any Linux FTP site for the LDP (Linux Documentation␊ |
| 43 | Project) books. This README is not meant to be documentation on the␊ |
| 44 | system: there are much better sources available.␊ |
| 45 | ␊ |
| 46 | - There are various README files in the Documentation/ subdirectory:␊ |
| 47 | these typically contain kernel-specific installation notes for some ␊ |
| 48 | drivers for example. See Documentation/00-INDEX for a list of what␊ |
| 49 | is contained in each file. Please read the Changes file, as it␊ |
| 50 | contains information about the problems, which may result by upgrading␊ |
| 51 | your kernel.␊ |
| 52 | ␊ |
| 53 | - The Documentation/DocBook/ subdirectory contains several guides for␊ |
| 54 | kernel developers and users. These guides can be rendered in a␊ |
| 55 | number of formats: PostScript (.ps), PDF, and HTML, among others.␊ |
| 56 | After installation, "make psdocs", "make pdfdocs", or "make htmldocs"␊ |
| 57 | will render the documentation in the requested format.␊ |
| 58 | ␊ |
| 59 | INSTALLING the kernel:␊ |
| 60 | ␊ |
| 61 | - If you install the full sources, put the kernel tarball in a␊ |
| 62 | directory where you have permissions (eg. your home directory) and␊ |
| 63 | unpack it:␊ |
| 64 | ␊ |
| 65 | ␉␉gzip -cd linux-2.6.XX.tar.gz | tar xvf -␊ |
| 66 | ␊ |
| 67 | or␊ |
| 68 | ␉␉bzip2 -dc linux-2.6.XX.tar.bz2 | tar xvf -␊ |
| 69 | ␊ |
| 70 | ␊ |
| 71 | Replace "XX" with the version number of the latest kernel.␊ |
| 72 | ␊ |
| 73 | Do NOT use the /usr/src/linux area! This area has a (usually␊ |
| 74 | incomplete) set of kernel headers that are used by the library header␊ |
| 75 | files. They should match the library, and not get messed up by␊ |
| 76 | whatever the kernel-du-jour happens to be.␊ |
| 77 | ␊ |
| 78 | - You can also upgrade between 2.6.xx releases by patching. Patches are␊ |
| 79 | distributed in the traditional gzip and the newer bzip2 format. To␊ |
| 80 | install by patching, get all the newer patch files, enter the␊ |
| 81 | top level directory of the kernel source (linux-2.6.xx) and execute:␊ |
| 82 | ␊ |
| 83 | ␉␉gzip -cd ../patch-2.6.xx.gz | patch -p1␊ |
| 84 | ␊ |
| 85 | or␊ |
| 86 | ␉␉bzip2 -dc ../patch-2.6.xx.bz2 | patch -p1␊ |
| 87 | ␊ |
| 88 | (repeat xx for all versions bigger than the version of your current␊ |
| 89 | source tree, _in_order_) and you should be ok. You may want to remove␊ |
| 90 | the backup files (xxx~ or xxx.orig), and make sure that there are no␊ |
| 91 | failed patches (xxx# or xxx.rej). If there are, either you or me has␊ |
| 92 | made a mistake.␊ |
| 93 | ␊ |
| 94 | Unlike patches for the 2.6.x kernels, patches for the 2.6.x.y kernels␊ |
| 95 | (also known as the -stable kernels) are not incremental but instead apply␊ |
| 96 | directly to the base 2.6.x kernel. Please read␊ |
| 97 | Documentation/applying-patches.txt for more information.␊ |
| 98 | ␊ |
| 99 | Alternatively, the script patch-kernel can be used to automate this␊ |
| 100 | process. It determines the current kernel version and applies any␊ |
| 101 | patches found.␊ |
| 102 | ␊ |
| 103 | ␉␉linux/scripts/patch-kernel linux␊ |
| 104 | ␊ |
| 105 | The first argument in the command above is the location of the␊ |
| 106 | kernel source. Patches are applied from the current directory, but␊ |
| 107 | an alternative directory can be specified as the second argument.␊ |
| 108 | ␊ |
| 109 | - If you are upgrading between releases using the stable series patches␊ |
| 110 | (for example, patch-2.6.xx.y), note that these "dot-releases" are␊ |
| 111 | not incremental and must be applied to the 2.6.xx base tree. For␊ |
| 112 | example, if your base kernel is 2.6.12 and you want to apply the␊ |
| 113 | 2.6.12.3 patch, you do not and indeed must not first apply the␊ |
| 114 | 2.6.12.1 and 2.6.12.2 patches. Similarly, if you are running kernel␊ |
| 115 | version 2.6.12.2 and want to jump to 2.6.12.3, you must first␊ |
| 116 | reverse the 2.6.12.2 patch (that is, patch -R) _before_ applying␊ |
| 117 | the 2.6.12.3 patch.␊ |
| 118 | You can read more on this in Documentation/applying-patches.txt␊ |
| 119 | ␊ |
| 120 | - Make sure you have no stale .o files and dependencies lying around:␊ |
| 121 | ␊ |
| 122 | ␉␉cd linux␊ |
| 123 | ␉␉make mrproper␊ |
| 124 | ␊ |
| 125 | You should now have the sources correctly installed.␊ |
| 126 | ␊ |
| 127 | SOFTWARE REQUIREMENTS␊ |
| 128 | ␊ |
| 129 | Compiling and running the 2.6.xx kernels requires up-to-date␊ |
| 130 | versions of various software packages. Consult␊ |
| 131 | Documentation/Changes for the minimum version numbers required␊ |
| 132 | and how to get updates for these packages. Beware that using␊ |
| 133 | excessively old versions of these packages can cause indirect␊ |
| 134 | errors that are very difficult to track down, so don't assume that␊ |
| 135 | you can just update packages when obvious problems arise during␊ |
| 136 | build or operation.␊ |
| 137 | ␊ |
| 138 | BUILD directory for the kernel:␊ |
| 139 | ␊ |
| 140 | When compiling the kernel all output files will per default be␊ |
| 141 | stored together with the kernel source code.␊ |
| 142 | Using the option "make O=output/dir" allow you to specify an alternate␊ |
| 143 | place for the output files (including .config).␊ |
| 144 | Example:␊ |
| 145 | kernel source code:␉/usr/src/linux-2.6.N␊ |
| 146 | build directory:␉␉/home/name/build/kernel␊ |
| 147 | ␊ |
| 148 | To configure and build the kernel use:␊ |
| 149 | cd /usr/src/linux-2.6.N␊ |
| 150 | make O=/home/name/build/kernel menuconfig␊ |
| 151 | make O=/home/name/build/kernel␊ |
| 152 | sudo make O=/home/name/build/kernel modules_install install␊ |
| 153 | ␊ |
| 154 | Please note: If the 'O=output/dir' option is used then it must be␊ |
| 155 | used for all invocations of make.␊ |
| 156 | ␊ |
| 157 | CONFIGURING the kernel:␊ |
| 158 | ␊ |
| 159 | Do not skip this step even if you are only upgrading one minor␊ |
| 160 | version. New configuration options are added in each release, and␊ |
| 161 | odd problems will turn up if the configuration files are not set up␊ |
| 162 | as expected. If you want to carry your existing configuration to a␊ |
| 163 | new version with minimal work, use "make oldconfig", which will␊ |
| 164 | only ask you for the answers to new questions.␊ |
| 165 | ␊ |
| 166 | - Alternate configuration commands are:␊ |
| 167 | ␉"make config" Plain text interface.␊ |
| 168 | ␉"make menuconfig" Text based color menus, radiolists & dialogs.␊ |
| 169 | ␉"make xconfig" X windows (Qt) based configuration tool.␊ |
| 170 | ␉"make gconfig" X windows (Gtk) based configuration tool.␊ |
| 171 | ␉"make oldconfig" Default all questions based on the contents of␊ |
| 172 | ␉␉␉ your existing ./.config file and asking about␊ |
| 173 | ␉␉␉ new config symbols.␊ |
| 174 | ␉"make silentoldconfig"␊ |
| 175 | ␉␉␉ Like above, but avoids cluttering the screen␊ |
| 176 | ␉␉␉ with questions already answered.␊ |
| 177 | ␉"make defconfig" Create a ./.config file by using the default␊ |
| 178 | ␉␉␉ symbol values from arch/$ARCH/defconfig.␊ |
| 179 | ␉"make allyesconfig"␊ |
| 180 | ␉␉␉ Create a ./.config file by setting symbol␊ |
| 181 | ␉␉␉ values to 'y' as much as possible.␊ |
| 182 | ␉"make allmodconfig"␊ |
| 183 | ␉␉␉ Create a ./.config file by setting symbol␊ |
| 184 | ␉␉␉ values to 'm' as much as possible.␊ |
| 185 | ␉"make allnoconfig" Create a ./.config file by setting symbol␊ |
| 186 | ␉␉␉ values to 'n' as much as possible.␊ |
| 187 | ␉"make randconfig" Create a ./.config file by setting symbol␊ |
| 188 | ␉␉␉ values to random values.␊ |
| 189 | ␊ |
| 190 | The allyesconfig/allmodconfig/allnoconfig/randconfig variants can␊ |
| 191 | also use the environment variable KCONFIG_ALLCONFIG to specify a␊ |
| 192 | filename that contains config options that the user requires to be␊ |
| 193 | set to a specific value. If KCONFIG_ALLCONFIG=filename is not used,␊ |
| 194 | "make *config" checks for a file named "all{yes/mod/no/random}.config"␊ |
| 195 | for symbol values that are to be forced. If this file is not found,␊ |
| 196 | it checks for a file named "all.config" to contain forced values.␊ |
| 197 | ␊ |
| 198 | ␉NOTES on "make config":␊ |
| 199 | ␉- having unnecessary drivers will make the kernel bigger, and can␊ |
| 200 | ␉ under some circumstances lead to problems: probing for a␊ |
| 201 | ␉ nonexistent controller card may confuse your other controllers␊ |
| 202 | ␉- compiling the kernel with "Processor type" set higher than 386␊ |
| 203 | ␉ will result in a kernel that does NOT work on a 386. The␊ |
| 204 | ␉ kernel will detect this on bootup, and give up.␊ |
| 205 | ␉- A kernel with math-emulation compiled in will still use the␊ |
| 206 | ␉ coprocessor if one is present: the math emulation will just␊ |
| 207 | ␉ never get used in that case. The kernel will be slightly larger,␊ |
| 208 | ␉ but will work on different machines regardless of whether they␊ |
| 209 | ␉ have a math coprocessor or not. ␊ |
| 210 | ␉- the "kernel hacking" configuration details usually result in a␊ |
| 211 | ␉ bigger or slower kernel (or both), and can even make the kernel␊ |
| 212 | ␉ less stable by configuring some routines to actively try to␊ |
| 213 | ␉ break bad code to find kernel problems (kmalloc()). Thus you␊ |
| 214 | ␉ should probably answer 'n' to the questions for␊ |
| 215 | "development", "experimental", or "debugging" features.␊ |
| 216 | ␊ |
| 217 | COMPILING the kernel:␊ |
| 218 | ␊ |
| 219 | - Make sure you have at least gcc 3.2 available.␊ |
| 220 | For more information, refer to Documentation/Changes.␊ |
| 221 | ␊ |
| 222 | Please note that you can still run a.out user programs with this kernel.␊ |
| 223 | ␊ |
| 224 | - Do a "make" to create a compressed kernel image. It is also␊ |
| 225 | possible to do "make install" if you have lilo installed to suit the␊ |
| 226 | kernel makefiles, but you may want to check your particular lilo setup first.␊ |
| 227 | ␊ |
| 228 | To do the actual install you have to be root, but none of the normal␊ |
| 229 | build should require that. Don't take the name of root in vain.␊ |
| 230 | ␊ |
| 231 | - If you configured any of the parts of the kernel as `modules', you␊ |
| 232 | will also have to do "make modules_install".␊ |
| 233 | ␊ |
| 234 | - Keep a backup kernel handy in case something goes wrong. This is ␊ |
| 235 | especially true for the development releases, since each new release␊ |
| 236 | contains new code which has not been debugged. Make sure you keep a␊ |
| 237 | backup of the modules corresponding to that kernel, as well. If you␊ |
| 238 | are installing a new kernel with the same version number as your␊ |
| 239 | working kernel, make a backup of your modules directory before you␊ |
| 240 | do a "make modules_install".␊ |
| 241 | Alternatively, before compiling, use the kernel config option␊ |
| 242 | "LOCALVERSION" to append a unique suffix to the regular kernel version.␊ |
| 243 | LOCALVERSION can be set in the "General Setup" menu.␊ |
| 244 | ␊ |
| 245 | - In order to boot your new kernel, you'll need to copy the kernel␊ |
| 246 | image (e.g. .../linux/arch/i386/boot/bzImage after compilation)␊ |
| 247 | to the place where your regular bootable kernel is found. ␊ |
| 248 | ␊ |
| 249 | - Booting a kernel directly from a floppy without the assistance of a␊ |
| 250 | bootloader such as LILO, is no longer supported.␊ |
| 251 | ␊ |
| 252 | If you boot Linux from the hard drive, chances are you use LILO which␊ |
| 253 | uses the kernel image as specified in the file /etc/lilo.conf. The␊ |
| 254 | kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or␊ |
| 255 | /boot/bzImage. To use the new kernel, save a copy of the old image␊ |
| 256 | and copy the new image over the old one. Then, you MUST RERUN LILO␊ |
| 257 | to update the loading map!! If you don't, you won't be able to boot␊ |
| 258 | the new kernel image.␊ |
| 259 | ␊ |
| 260 | Reinstalling LILO is usually a matter of running /sbin/lilo. ␊ |
| 261 | You may wish to edit /etc/lilo.conf to specify an entry for your␊ |
| 262 | old kernel image (say, /vmlinux.old) in case the new one does not␊ |
| 263 | work. See the LILO docs for more information. ␊ |
| 264 | ␊ |
| 265 | After reinstalling LILO, you should be all set. Shutdown the system,␊ |
| 266 | reboot, and enjoy!␊ |
| 267 | ␊ |
| 268 | If you ever need to change the default root device, video mode,␊ |
| 269 | ramdisk size, etc. in the kernel image, use the 'rdev' program (or␊ |
| 270 | alternatively the LILO boot options when appropriate). No need to␊ |
| 271 | recompile the kernel to change these parameters. ␊ |
| 272 | ␊ |
| 273 | - Reboot with the new kernel and enjoy. ␊ |
| 274 | ␊ |
| 275 | IF SOMETHING GOES WRONG:␊ |
| 276 | ␊ |
| 277 | - If you have problems that seem to be due to kernel bugs, please check␊ |
| 278 | the file MAINTAINERS to see if there is a particular person associated␊ |
| 279 | with the part of the kernel that you are having trouble with. If there␊ |
| 280 | isn't anyone listed there, then the second best thing is to mail␊ |
| 281 | them to me (torvalds@linux-foundation.org), and possibly to any other␊ |
| 282 | relevant mailing-list or to the newsgroup.␊ |
| 283 | ␊ |
| 284 | - In all bug-reports, *please* tell what kernel you are talking about,␊ |
| 285 | how to duplicate the problem, and what your setup is (use your common␊ |
| 286 | sense). If the problem is new, tell me so, and if the problem is␊ |
| 287 | old, please try to tell me when you first noticed it.␊ |
| 288 | ␊ |
| 289 | - If the bug results in a message like␊ |
| 290 | ␊ |
| 291 | ␉unable to handle kernel paging request at address C0000010␊ |
| 292 | ␉Oops: 0002␊ |
| 293 | ␉EIP: 0010:XXXXXXXX␊ |
| 294 | ␉eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx␊ |
| 295 | ␉esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx␊ |
| 296 | ␉ds: xxxx es: xxxx fs: xxxx gs: xxxx␊ |
| 297 | ␉Pid: xx, process nr: xx␊ |
| 298 | ␉xx xx xx xx xx xx xx xx xx xx␊ |
| 299 | ␊ |
| 300 | or similar kernel debugging information on your screen or in your␊ |
| 301 | system log, please duplicate it *exactly*. The dump may look␊ |
| 302 | incomprehensible to you, but it does contain information that may␊ |
| 303 | help debugging the problem. The text above the dump is also␊ |
| 304 | important: it tells something about why the kernel dumped code (in␊ |
| 305 | the above example it's due to a bad kernel pointer). More information␊ |
| 306 | on making sense of the dump is in Documentation/oops-tracing.txt␊ |
| 307 | ␊ |
| 308 | - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump␊ |
| 309 | as is, otherwise you will have to use the "ksymoops" program to make␊ |
| 310 | sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).␊ |
| 311 | This utility can be downloaded from␊ |
| 312 | ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .␊ |
| 313 | Alternately you can do the dump lookup by hand:␊ |
| 314 | ␊ |
| 315 | - In debugging dumps like the above, it helps enormously if you can␊ |
| 316 | look up what the EIP value means. The hex value as such doesn't help␊ |
| 317 | me or anybody else very much: it will depend on your particular␊ |
| 318 | kernel setup. What you should do is take the hex value from the EIP␊ |
| 319 | line (ignore the "0010:"), and look it up in the kernel namelist to␊ |
| 320 | see which kernel function contains the offending address.␊ |
| 321 | ␊ |
| 322 | To find out the kernel function name, you'll need to find the system␊ |
| 323 | binary associated with the kernel that exhibited the symptom. This is␊ |
| 324 | the file 'linux/vmlinux'. To extract the namelist and match it against␊ |
| 325 | the EIP from the kernel crash, do:␊ |
| 326 | ␊ |
| 327 | ␉␉nm vmlinux | sort | less␊ |
| 328 | ␊ |
| 329 | This will give you a list of kernel addresses sorted in ascending␊ |
| 330 | order, from which it is simple to find the function that contains the␊ |
| 331 | offending address. Note that the address given by the kernel␊ |
| 332 | debugging messages will not necessarily match exactly with the␊ |
| 333 | function addresses (in fact, that is very unlikely), so you can't␊ |
| 334 | just 'grep' the list: the list will, however, give you the starting␊ |
| 335 | point of each kernel function, so by looking for the function that␊ |
| 336 | has a starting address lower than the one you are searching for but␊ |
| 337 | is followed by a function with a higher address you will find the one␊ |
| 338 | you want. In fact, it may be a good idea to include a bit of␊ |
| 339 | "context" in your problem report, giving a few lines around the␊ |
| 340 | interesting one. ␊ |
| 341 | ␊ |
| 342 | If you for some reason cannot do the above (you have a pre-compiled␊ |
| 343 | kernel image or similar), telling me as much about your setup as␊ |
| 344 | possible will help. Please read the REPORTING-BUGS document for details.␊ |
| 345 | ␊ |
| 346 | - Alternately, you can use gdb on a running kernel. (read-only; i.e. you␊ |
| 347 | cannot change values or set break points.) To do this, first compile the␊ |
| 348 | kernel with -g; edit arch/i386/Makefile appropriately, then do a "make␊ |
| 349 | clean". You'll also need to enable CONFIG_PROC_FS (via "make config").␊ |
| 350 | ␊ |
| 351 | After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".␊ |
| 352 | You can now use all the usual gdb commands. The command to look up the␊ |
| 353 | point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes␊ |
| 354 | with the EIP value.)␊ |
| 355 | ␊ |
| 356 | gdb'ing a non-running kernel currently fails because gdb (wrongly)␊ |
| 357 | disregards the starting offset for which the kernel is compiled.␊ |
| 358 | ␊ |
| 359 | |
