1 Linux kernel release 2.4.xx 2 3These are the release notes for Linux version 2.4. Read them carefully, 4as they tell you what this is all about, explain how to install the 5kernel, and what to do if something goes wrong. 6 7WHAT IS LINUX? 8 9 Linux is a Unix clone written from scratch by Linus Torvalds with 10 assistance from a loosely-knit team of hackers across the Net. 11 It aims towards POSIX compliance. 12 13 It has all the features you would expect in a modern fully-fledged 14 Unix, including true multitasking, virtual memory, shared libraries, 15 demand loading, shared copy-on-write executables, proper memory 16 management and TCP/IP networking. 17 18 It is distributed under the GNU General Public License - see the 19 accompanying COPYING file for more details. 20 21ON WHAT HARDWARE DOES IT RUN? 22 23 Linux was first developed for 386/486-based PCs. These days it also 24 runs on ARMs, DEC Alphas, SUN Sparcs, M68000 machines (like Atari and 25 Amiga), MIPS and PowerPC, and others. 26 27DOCUMENTATION: 28 29 - There is a lot of documentation available both in electronic form on 30 the Internet and in books, both Linux-specific and pertaining to 31 general UNIX questions. I'd recommend looking into the documentation 32 subdirectories on any Linux FTP site for the LDP (Linux Documentation 33 Project) books. This README is not meant to be documentation on the 34 system: there are much better sources available. 35 36 - There are various README files in the Documentation/ subdirectory: 37 these typically contain kernel-specific installation notes for some 38 drivers for example. See ./Documentation/00-INDEX for a list of what 39 is contained in each file. Please read the Changes file, as it 40 contains information about the problems, which may result by upgrading 41 your kernel. 42 43 - The Documentation/DocBook/ subdirectory contains several guides for 44 kernel developers and users. These guides can be rendered in a 45 number of formats: PostScript (.ps), PDF, and HTML, among others. 46 After installation, "make psdocs", "make pdfdocs", or "make htmldocs" 47 will render the documentation in the requested format. 48 49INSTALLING the kernel: 50 51 - If you install the full sources, put the kernel tarball in a 52 directory where you have permissions (eg. your home directory) and 53 unpack it: 54 55 gzip -cd linux-2.4.XX.tar.gz | tar xvf - 56 57 Replace "XX" with the version number of the latest kernel. 58 59 Do NOT use the /usr/src/linux area! This area has a (usually 60 incomplete) set of kernel headers that are used by the library header 61 files. They should match the library, and not get messed up by 62 whatever the kernel-du-jour happens to be. 63 64 - You can also upgrade between 2.4.xx releases by patching. Patches are 65 distributed in the traditional gzip and the new bzip2 format. To 66 install by patching, get all the newer patch files, enter the 67 top level directory of the kernel source (linux-2.4.xx) and execute: 68 69 gzip -cd ../patch-2.4.xx.gz | patch -p1 70 71 or 72 bzip2 -dc ../patch-2.4.xx.bz2 | patch -p1 73 74 (repeat xx for all versions bigger than the version of your current 75 source tree, _in_order_) and you should be ok. You may want to remove 76 the backup files (xxx~ or xxx.orig), and make sure that there are no 77 failed patches (xxx# or xxx.rej). If there are, either you or me has 78 made a mistake. 79 80 Alternatively, the script patch-kernel can be used to automate this 81 process. It determines the current kernel version and applies any 82 patches found. 83 84 linux/scripts/patch-kernel linux 85 86 The first argument in the command above is the location of the 87 kernel source. Patches are applied from the current directory, but 88 an alternative directory can be specified as the second argument. 89 90 - Make sure you have no stale .o files and dependencies lying around: 91 92 cd linux 93 make mrproper 94 95 You should now have the sources correctly installed. 96 97SOFTWARE REQUIREMENTS 98 99 Compiling and running the 2.4.xx kernels requires up-to-date 100 versions of various software packages. Consult 101 ./Documentation/Changes for the minimum version numbers required 102 and how to get updates for these packages. Beware that using 103 excessively old versions of these packages can cause indirect 104 errors that are very difficult to track down, so don't assume that 105 you can just update packages when obvious problems arise during 106 build or operation. 107 108CONFIGURING the kernel: 109 110 - Do a "make config" to configure the basic kernel. "make config" needs 111 bash to work: it will search for bash in $BASH, /bin/bash and /bin/sh 112 (in that order), so one of those must be correct for it to work. 113 114 Do not skip this step even if you are only upgrading one minor 115 version. New configuration options are added in each release, and 116 odd problems will turn up if the configuration files are not set up 117 as expected. If you want to carry your existing configuration to a 118 new version with minimal work, use "make oldconfig", which will 119 only ask you for the answers to new questions. 120 121 - Alternate configuration commands are: 122 "make menuconfig" Text based color menus, radiolists & dialogs. 123 "make xconfig" X windows based configuration tool. 124 "make oldconfig" Default all questions based on the contents of 125 your existing ./.config file. 126 127 NOTES on "make config": 128 - having unnecessary drivers will make the kernel bigger, and can 129 under some circumstances lead to problems: probing for a 130 nonexistent controller card may confuse your other controllers 131 - compiling the kernel with "Processor type" set higher than 386 132 will result in a kernel that does NOT work on a 386. The 133 kernel will detect this on bootup, and give up. 134 - A kernel with math-emulation compiled in will still use the 135 coprocessor if one is present: the math emulation will just 136 never get used in that case. The kernel will be slightly larger, 137 but will work on different machines regardless of whether they 138 have a math coprocessor or not. 139 - the "kernel hacking" configuration details usually result in a 140 bigger or slower kernel (or both), and can even make the kernel 141 less stable by configuring some routines to actively try to 142 break bad code to find kernel problems (kmalloc()). Thus you 143 should probably answer 'n' to the questions for 144 "development", "experimental", or "debugging" features. 145 146 - Check the top Makefile for further site-dependent configuration 147 (default SVGA mode etc). 148 149 - Finally, do a "make dep" to set up all the dependencies correctly. 150 151COMPILING the kernel: 152 153 - Make sure you have gcc 2.95.3 available. gcc 2.91.66 (egcs-1.1.2) may 154 also work but is not as safe, and *gcc 2.7.2.3 is no longer supported*. 155 gcc 4 is *not* supported. 156 Also remember to upgrade your binutils package (for as/ld/nm and company) 157 if necessary. For more information, refer to ./Documentation/Changes. 158 159 Please note that you can still run a.out user programs with this kernel. 160 161 - Do a "make bzImage" to create a compressed kernel image. If you want 162 to make a boot disk (without root filesystem or LILO), insert a floppy 163 in your A: drive, and do a "make bzdisk". It is also possible to do 164 "make install" if you have lilo installed to suit the kernel makefiles, 165 but you may want to check your particular lilo setup first. 166 167 To do the actual install you have to be root, but none of the normal 168 build should require that. Don't take the name of root in vain. 169 170 - In the unlikely event that your system cannot boot bzImage kernels you 171 can still compile your kernel as zImage. However, since zImage support 172 will be removed at some point in the future in favor of bzImage we 173 encourage people having problems with booting bzImage kernels to report 174 these, with detailed hardware configuration information, to the 175 linux-kernel mailing list and to H. Peter Anvin <hpa+linux@zytor.com>. 176 177 - If you configured any of the parts of the kernel as `modules', you 178 will have to do "make modules" followed by "make modules_install". 179 Read Documentation/modules.txt for more information. For example, 180 an explanation of how to use the modules is included there. 181 182 - Keep a backup kernel handy in case something goes wrong. This is 183 especially true for the development releases, since each new release 184 contains new code which has not been debugged. Make sure you keep a 185 backup of the modules corresponding to that kernel, as well. If you 186 are installing a new kernel with the same version number as your 187 working kernel, make a backup of your modules directory before you 188 do a "make modules_install". 189 190 - In order to boot your new kernel, you'll need to copy the kernel 191 image (found in .../linux/arch/i386/boot/bzImage after compilation) 192 to the place where your regular bootable kernel is found. 193 194 For some, this is on a floppy disk, in which case you can copy the 195 kernel bzImage file to /dev/fd0 to make a bootable floppy. 196 197 If you boot Linux from the hard drive, chances are you use LILO which 198 uses the kernel image as specified in the file /etc/lilo.conf. The 199 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or 200 /boot/bzImage. To use the new kernel, save a copy of the old image 201 and copy the new image over the old one. Then, you MUST RERUN LILO 202 to update the loading map!! If you don't, you won't be able to boot 203 the new kernel image. 204 205 Reinstalling LILO is usually a matter of running /sbin/lilo. 206 You may wish to edit /etc/lilo.conf to specify an entry for your 207 old kernel image (say, /vmlinux.old) in case the new one does not 208 work. See the LILO docs for more information. 209 210 After reinstalling LILO, you should be all set. Shutdown the system, 211 reboot, and enjoy! 212 213 If you ever need to change the default root device, video mode, 214 ramdisk size, etc. in the kernel image, use the 'rdev' program (or 215 alternatively the LILO boot options when appropriate). No need to 216 recompile the kernel to change these parameters. 217 218 - Reboot with the new kernel and enjoy. 219 220IF SOMETHING GOES WRONG: 221 222 - If you have problems that seem to be due to kernel bugs, please check 223 the file MAINTAINERS to see if there is a particular person associated 224 with the part of the kernel that you are having trouble with. If there 225 isn't anyone listed there, then the second best thing is to mail 226 them to me (torvalds@transmeta.com), and possibly to any other 227 relevant mailing-list or to the newsgroup. The mailing-lists are 228 useful especially for SCSI and networking problems, as I can't test 229 either of those personally anyway. 230 231 - In all bug-reports, *please* tell what kernel you are talking about, 232 how to duplicate the problem, and what your setup is (use your common 233 sense). If the problem is new, tell me so, and if the problem is 234 old, please try to tell me when you first noticed it. 235 236 - If the bug results in a message like 237 238 unable to handle kernel paging request at address C0000010 239 Oops: 0002 240 EIP: 0010:XXXXXXXX 241 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx 242 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx 243 ds: xxxx es: xxxx fs: xxxx gs: xxxx 244 Pid: xx, process nr: xx 245 xx xx xx xx xx xx xx xx xx xx 246 247 or similar kernel debugging information on your screen or in your 248 system log, please duplicate it *exactly*. The dump may look 249 incomprehensible to you, but it does contain information that may 250 help debugging the problem. The text above the dump is also 251 important: it tells something about why the kernel dumped code (in 252 the above example it's due to a bad kernel pointer). More information 253 on making sense of the dump is in Documentation/oops-tracing.txt 254 255 - You can use the "ksymoops" program to make sense of the dump. This 256 utility can be downloaded from 257 ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops. 258 Alternately you can do the dump lookup by hand: 259 260 - In debugging dumps like the above, it helps enormously if you can 261 look up what the EIP value means. The hex value as such doesn't help 262 me or anybody else very much: it will depend on your particular 263 kernel setup. What you should do is take the hex value from the EIP 264 line (ignore the "0010:"), and look it up in the kernel namelist to 265 see which kernel function contains the offending address. 266 267 To find out the kernel function name, you'll need to find the system 268 binary associated with the kernel that exhibited the symptom. This is 269 the file 'linux/vmlinux'. To extract the namelist and match it against 270 the EIP from the kernel crash, do: 271 272 nm vmlinux | sort | less 273 274 This will give you a list of kernel addresses sorted in ascending 275 order, from which it is simple to find the function that contains the 276 offending address. Note that the address given by the kernel 277 debugging messages will not necessarily match exactly with the 278 function addresses (in fact, that is very unlikely), so you can't 279 just 'grep' the list: the list will, however, give you the starting 280 point of each kernel function, so by looking for the function that 281 has a starting address lower than the one you are searching for but 282 is followed by a function with a higher address you will find the one 283 you want. In fact, it may be a good idea to include a bit of 284 "context" in your problem report, giving a few lines around the 285 interesting one. 286 287 If you for some reason cannot do the above (you have a pre-compiled 288 kernel image or similar), telling me as much about your setup as 289 possible will help. 290 291 - Alternately, you can use gdb on a running kernel. (read-only; i.e. you 292 cannot change values or set break points.) To do this, first compile the 293 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make 294 clean". You'll also need to enable CONFIG_PROC_FS (via "make config"). 295 296 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore". 297 You can now use all the usual gdb commands. The command to look up the 298 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes 299 with the EIP value.) 300 301 gdb'ing a non-running kernel currently fails because gdb (wrongly) 302 disregards the starting offset for which the kernel is compiled. 303 304