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754c7976 | 1 | |
9299c3e9 MCC |
2 | Applying Patches To The Linux Kernel |
3 | ++++++++++++++++++++++++++++++++++++ | |
754c7976 | 4 | |
9299c3e9 MCC |
5 | Original by: |
6 | Jesper Juhl, August 2005 | |
7 | ||
8 | Last update: | |
9 | 2006-01-05 | |
754c7976 JJ |
10 | |
11 | ||
12 | A frequently asked question on the Linux Kernel Mailing List is how to apply | |
13 | a patch to the kernel or, more specifically, what base kernel a patch for | |
14 | one of the many trees/branches should be applied to. Hopefully this document | |
15 | will explain this to you. | |
16 | ||
17 | In addition to explaining how to apply and revert patches, a brief | |
18 | description of the different kernel trees (and examples of how to apply | |
19 | their specific patches) is also provided. | |
20 | ||
21 | ||
22 | What is a patch? | |
9299c3e9 MCC |
23 | ================ |
24 | ||
25 | A patch is a small text document containing a delta of changes between two | |
26 | different versions of a source tree. Patches are created with the ``diff`` | |
754c7976 | 27 | program. |
9299c3e9 | 28 | |
754c7976 JJ |
29 | To correctly apply a patch you need to know what base it was generated from |
30 | and what new version the patch will change the source tree into. These | |
31 | should both be present in the patch file metadata or be possible to deduce | |
32 | from the filename. | |
33 | ||
34 | ||
35 | How do I apply or revert a patch? | |
9299c3e9 MCC |
36 | ================================= |
37 | ||
38 | You apply a patch with the ``patch`` program. The patch program reads a diff | |
754c7976 JJ |
39 | (or patch) file and makes the changes to the source tree described in it. |
40 | ||
41 | Patches for the Linux kernel are generated relative to the parent directory | |
42 | holding the kernel source dir. | |
43 | ||
44 | This means that paths to files inside the patch file contain the name of the | |
45 | kernel source directories it was generated against (or some other directory | |
46 | names like "a/" and "b/"). | |
9299c3e9 | 47 | |
754c7976 JJ |
48 | Since this is unlikely to match the name of the kernel source dir on your |
49 | local machine (but is often useful info to see what version an otherwise | |
50 | unlabeled patch was generated against) you should change into your kernel | |
51 | source directory and then strip the first element of the path from filenames | |
9299c3e9 MCC |
52 | in the patch file when applying it (the ``-p1`` argument to ``patch`` does |
53 | this). | |
754c7976 JJ |
54 | |
55 | To revert a previously applied patch, use the -R argument to patch. | |
56 | So, if you applied a patch like this: | |
9299c3e9 MCC |
57 | |
58 | :: | |
59 | ||
754c7976 JJ |
60 | patch -p1 < ../patch-x.y.z |
61 | ||
62 | You can revert (undo) it like this: | |
9299c3e9 MCC |
63 | |
64 | :: | |
65 | ||
754c7976 JJ |
66 | patch -R -p1 < ../patch-x.y.z |
67 | ||
68 | ||
9299c3e9 MCC |
69 | How do I feed a patch/diff file to ``patch``? |
70 | ============================================= | |
71 | ||
72 | This (as usual with Linux and other UNIX like operating systems) can be | |
754c7976 | 73 | done in several different ways. |
9299c3e9 | 74 | |
754c7976 JJ |
75 | In all the examples below I feed the file (in uncompressed form) to patch |
76 | via stdin using the following syntax: | |
9299c3e9 MCC |
77 | |
78 | :: | |
79 | ||
754c7976 JJ |
80 | patch -p1 < path/to/patch-x.y.z |
81 | ||
82 | If you just want to be able to follow the examples below and don't want to | |
83 | know of more than one way to use patch, then you can stop reading this | |
84 | section here. | |
85 | ||
86 | Patch can also get the name of the file to use via the -i argument, like | |
87 | this: | |
9299c3e9 MCC |
88 | |
89 | :: | |
90 | ||
754c7976 JJ |
91 | patch -p1 -i path/to/patch-x.y.z |
92 | ||
93 | If your patch file is compressed with gzip or bzip2 and you don't want to | |
94 | uncompress it before applying it, then you can feed it to patch like this | |
95 | instead: | |
9299c3e9 MCC |
96 | |
97 | :: | |
98 | ||
754c7976 JJ |
99 | zcat path/to/patch-x.y.z.gz | patch -p1 |
100 | bzcat path/to/patch-x.y.z.bz2 | patch -p1 | |
101 | ||
102 | If you wish to uncompress the patch file by hand first before applying it | |
103 | (what I assume you've done in the examples below), then you simply run | |
c594a50d | 104 | gunzip or bunzip2 on the file -- like this: |
9299c3e9 MCC |
105 | |
106 | :: | |
107 | ||
754c7976 JJ |
108 | gunzip patch-x.y.z.gz |
109 | bunzip2 patch-x.y.z.bz2 | |
110 | ||
111 | Which will leave you with a plain text patch-x.y.z file that you can feed to | |
9299c3e9 | 112 | patch via stdin or the ``-i`` argument, as you prefer. |
754c7976 | 113 | |
9299c3e9 | 114 | A few other nice arguments for patch are ``-s`` which causes patch to be silent |
754c7976 | 115 | except for errors which is nice to prevent errors from scrolling out of the |
9299c3e9 MCC |
116 | screen too fast, and ``--dry-run`` which causes patch to just print a listing of |
117 | what would happen, but doesn't actually make any changes. Finally ``--verbose`` | |
754c7976 JJ |
118 | tells patch to print more information about the work being done. |
119 | ||
120 | ||
121 | Common errors when patching | |
9299c3e9 MCC |
122 | =========================== |
123 | ||
124 | When patch applies a patch file it attempts to verify the sanity of the | |
754c7976 | 125 | file in different ways. |
9299c3e9 | 126 | |
2d69049a | 127 | Checking that the file looks like a valid patch file and checking the code |
754c7976 JJ |
128 | around the bits being modified matches the context provided in the patch are |
129 | just two of the basic sanity checks patch does. | |
130 | ||
131 | If patch encounters something that doesn't look quite right it has two | |
132 | options. It can either refuse to apply the changes and abort or it can try | |
133 | to find a way to make the patch apply with a few minor changes. | |
134 | ||
135 | One example of something that's not 'quite right' that patch will attempt to | |
136 | fix up is if all the context matches, the lines being changed match, but the | |
137 | line numbers are different. This can happen, for example, if the patch makes | |
138 | a change in the middle of the file but for some reasons a few lines have | |
139 | been added or removed near the beginning of the file. In that case | |
140 | everything looks good it has just moved up or down a bit, and patch will | |
141 | usually adjust the line numbers and apply the patch. | |
142 | ||
143 | Whenever patch applies a patch that it had to modify a bit to make it fit | |
9299c3e9 | 144 | it'll tell you about it by saying the patch applied with **fuzz**. |
754c7976 JJ |
145 | You should be wary of such changes since even though patch probably got it |
146 | right it doesn't /always/ get it right, and the result will sometimes be | |
147 | wrong. | |
148 | ||
149 | When patch encounters a change that it can't fix up with fuzz it rejects it | |
9299c3e9 | 150 | outright and leaves a file with a ``.rej`` extension (a reject file). You can |
90f2447d | 151 | read this file to see exactly what change couldn't be applied, so you can |
754c7976 JJ |
152 | go fix it up by hand if you wish. |
153 | ||
c594a50d | 154 | If you don't have any third-party patches applied to your kernel source, but |
754c7976 JJ |
155 | only patches from kernel.org and you apply the patches in the correct order, |
156 | and have made no modifications yourself to the source files, then you should | |
157 | never see a fuzz or reject message from patch. If you do see such messages | |
158 | anyway, then there's a high risk that either your local source tree or the | |
159 | patch file is corrupted in some way. In that case you should probably try | |
90f2447d | 160 | re-downloading the patch and if things are still not OK then you'd be advised |
754c7976 JJ |
161 | to start with a fresh tree downloaded in full from kernel.org. |
162 | ||
163 | Let's look a bit more at some of the messages patch can produce. | |
164 | ||
9299c3e9 | 165 | If patch stops and presents a ``File to patch:`` prompt, then patch could not |
754c7976 JJ |
166 | find a file to be patched. Most likely you forgot to specify -p1 or you are |
167 | in the wrong directory. Less often, you'll find patches that need to be | |
9299c3e9 | 168 | applied with ``-p0`` instead of ``-p1`` (reading the patch file should reveal if |
c594a50d | 169 | this is the case -- if so, then this is an error by the person who created |
754c7976 JJ |
170 | the patch but is not fatal). |
171 | ||
9299c3e9 | 172 | If you get ``Hunk #2 succeeded at 1887 with fuzz 2 (offset 7 lines).`` or a |
754c7976 JJ |
173 | message similar to that, then it means that patch had to adjust the location |
174 | of the change (in this example it needed to move 7 lines from where it | |
175 | expected to make the change to make it fit). | |
9299c3e9 | 176 | |
754c7976 JJ |
177 | The resulting file may or may not be OK, depending on the reason the file |
178 | was different than expected. | |
9299c3e9 | 179 | |
754c7976 JJ |
180 | This often happens if you try to apply a patch that was generated against a |
181 | different kernel version than the one you are trying to patch. | |
182 | ||
9299c3e9 | 183 | If you get a message like ``Hunk #3 FAILED at 2387.``, then it means that the |
754c7976 | 184 | patch could not be applied correctly and the patch program was unable to |
9299c3e9 MCC |
185 | fuzz its way through. This will generate a ``.rej`` file with the change that |
186 | caused the patch to fail and also a ``.orig`` file showing you the original | |
754c7976 JJ |
187 | content that couldn't be changed. |
188 | ||
9299c3e9 | 189 | If you get ``Reversed (or previously applied) patch detected! Assume -R? [n]`` |
754c7976 JJ |
190 | then patch detected that the change contained in the patch seems to have |
191 | already been made. | |
9299c3e9 | 192 | |
754c7976 JJ |
193 | If you actually did apply this patch previously and you just re-applied it |
194 | in error, then just say [n]o and abort this patch. If you applied this patch | |
195 | previously and actually intended to revert it, but forgot to specify -R, | |
9299c3e9 MCC |
196 | then you can say [**y**]es here to make patch revert it for you. |
197 | ||
754c7976 JJ |
198 | This can also happen if the creator of the patch reversed the source and |
199 | destination directories when creating the patch, and in that case reverting | |
200 | the patch will in fact apply it. | |
201 | ||
9299c3e9 MCC |
202 | A message similar to ``patch: **** unexpected end of file in patch`` or |
203 | ``patch unexpectedly ends in middle of line`` means that patch could make no | |
204 | sense of the file you fed to it. Either your download is broken, you tried to | |
205 | feed patch a compressed patch file without uncompressing it first, or the patch | |
c594a50d RD |
206 | file that you are using has been mangled by a mail client or mail transfer |
207 | agent along the way somewhere, e.g., by splitting a long line into two lines. | |
208 | Often these warnings can easily be fixed by joining (concatenating) the | |
209 | two lines that had been split. | |
754c7976 JJ |
210 | |
211 | As I already mentioned above, these errors should never happen if you apply | |
212 | a patch from kernel.org to the correct version of an unmodified source tree. | |
213 | So if you get these errors with kernel.org patches then you should probably | |
c594a50d | 214 | assume that either your patch file or your tree is broken and I'd advise you |
754c7976 JJ |
215 | to start over with a fresh download of a full kernel tree and the patch you |
216 | wish to apply. | |
217 | ||
218 | ||
9299c3e9 MCC |
219 | Are there any alternatives to ``patch``? |
220 | ======================================== | |
90f2447d | 221 | |
9299c3e9 MCC |
222 | |
223 | Yes there are alternatives. | |
224 | ||
225 | You can use the ``interdiff`` program (http://cyberelk.net/tim/patchutils/) to | |
90f2447d JJ |
226 | generate a patch representing the differences between two patches and then |
227 | apply the result. | |
9299c3e9 | 228 | |
754c7976 JJ |
229 | This will let you move from something like 2.6.12.2 to 2.6.12.3 in a single |
230 | step. The -z flag to interdiff will even let you feed it patches in gzip or | |
231 | bzip2 compressed form directly without the use of zcat or bzcat or manual | |
232 | decompression. | |
233 | ||
234 | Here's how you'd go from 2.6.12.2 to 2.6.12.3 in a single step: | |
9299c3e9 MCC |
235 | |
236 | :: | |
237 | ||
754c7976 JJ |
238 | interdiff -z ../patch-2.6.12.2.bz2 ../patch-2.6.12.3.gz | patch -p1 |
239 | ||
240 | Although interdiff may save you a step or two you are generally advised to | |
241 | do the additional steps since interdiff can get things wrong in some cases. | |
242 | ||
9299c3e9 | 243 | Another alternative is ``ketchup``, which is a python script for automatic |
754c7976 JJ |
244 | downloading and applying of patches (http://www.selenic.com/ketchup/). |
245 | ||
9299c3e9 | 246 | Other nice tools are diffstat, which shows a summary of changes made by a |
c594a50d RD |
247 | patch; lsdiff, which displays a short listing of affected files in a patch |
248 | file, along with (optionally) the line numbers of the start of each patch; | |
249 | and grepdiff, which displays a list of the files modified by a patch where | |
754c7976 JJ |
250 | the patch contains a given regular expression. |
251 | ||
252 | ||
253 | Where can I download the patches? | |
9299c3e9 MCC |
254 | ================================= |
255 | ||
256 | The patches are available at http://kernel.org/ | |
754c7976 JJ |
257 | Most recent patches are linked from the front page, but they also have |
258 | specific homes. | |
259 | ||
260 | The 2.6.x.y (-stable) and 2.6.x patches live at | |
9299c3e9 MCC |
261 | |
262 | ftp://ftp.kernel.org/pub/linux/kernel/v2.6/ | |
754c7976 JJ |
263 | |
264 | The -rc patches live at | |
9299c3e9 MCC |
265 | |
266 | ftp://ftp.kernel.org/pub/linux/kernel/v2.6/testing/ | |
754c7976 JJ |
267 | |
268 | The -git patches live at | |
9299c3e9 MCC |
269 | |
270 | ftp://ftp.kernel.org/pub/linux/kernel/v2.6/snapshots/ | |
754c7976 JJ |
271 | |
272 | The -mm kernels live at | |
754c7976 | 273 | |
9299c3e9 MCC |
274 | ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/ |
275 | ||
276 | In place of ``ftp.kernel.org`` you can use ``ftp.cc.kernel.org``, where cc is a | |
754c7976 JJ |
277 | country code. This way you'll be downloading from a mirror site that's most |
278 | likely geographically closer to you, resulting in faster downloads for you, | |
c594a50d RD |
279 | less bandwidth used globally and less load on the main kernel.org servers -- |
280 | these are good things, so do use mirrors when possible. | |
754c7976 JJ |
281 | |
282 | ||
283 | The 2.6.x kernels | |
9299c3e9 MCC |
284 | ================= |
285 | ||
286 | These are the base stable releases released by Linus. The highest numbered | |
754c7976 JJ |
287 | release is the most recent. |
288 | ||
c594a50d | 289 | If regressions or other serious flaws are found, then a -stable fix patch |
754c7976 JJ |
290 | will be released (see below) on top of this base. Once a new 2.6.x base |
291 | kernel is released, a patch is made available that is a delta between the | |
292 | previous 2.6.x kernel and the new one. | |
293 | ||
c594a50d | 294 | To apply a patch moving from 2.6.11 to 2.6.12, you'd do the following (note |
9299c3e9 | 295 | that such patches do **NOT** apply on top of 2.6.x.y kernels but on top of the |
c594a50d | 296 | base 2.6.x kernel -- if you need to move from 2.6.x.y to 2.6.x+1 you need to |
754c7976 JJ |
297 | first revert the 2.6.x.y patch). |
298 | ||
299 | Here are some examples: | |
300 | ||
9299c3e9 MCC |
301 | :: |
302 | ||
303 | # moving from 2.6.11 to 2.6.12 | |
304 | $ cd ~/linux-2.6.11 # change to kernel source dir | |
305 | $ patch -p1 < ../patch-2.6.12 # apply the 2.6.12 patch | |
306 | $ cd .. | |
307 | $ mv linux-2.6.11 linux-2.6.12 # rename source dir | |
754c7976 | 308 | |
9299c3e9 MCC |
309 | # moving from 2.6.11.1 to 2.6.12 |
310 | $ cd ~/linux-2.6.11.1 # change to kernel source dir | |
311 | $ patch -p1 -R < ../patch-2.6.11.1 # revert the 2.6.11.1 patch | |
312 | # source dir is now 2.6.11 | |
313 | $ patch -p1 < ../patch-2.6.12 # apply new 2.6.12 patch | |
314 | $ cd .. | |
315 | $ mv linux-2.6.11.1 linux-2.6.12 # rename source dir | |
754c7976 JJ |
316 | |
317 | ||
318 | The 2.6.x.y kernels | |
9299c3e9 MCC |
319 | =================== |
320 | ||
321 | Kernels with 4-digit versions are -stable kernels. They contain small(ish) | |
754c7976 JJ |
322 | critical fixes for security problems or significant regressions discovered |
323 | in a given 2.6.x kernel. | |
324 | ||
325 | This is the recommended branch for users who want the most recent stable | |
326 | kernel and are not interested in helping test development/experimental | |
327 | versions. | |
328 | ||
329 | If no 2.6.x.y kernel is available, then the highest numbered 2.6.x kernel is | |
330 | the current stable kernel. | |
331 | ||
9299c3e9 MCC |
332 | .. note:: |
333 | ||
334 | The -stable team usually do make incremental patches available as well | |
c594a50d RD |
335 | as patches against the latest mainline release, but I only cover the |
336 | non-incremental ones below. The incremental ones can be found at | |
337 | ftp://ftp.kernel.org/pub/linux/kernel/v2.6/incr/ | |
338 | ||
754c7976 JJ |
339 | These patches are not incremental, meaning that for example the 2.6.12.3 |
340 | patch does not apply on top of the 2.6.12.2 kernel source, but rather on top | |
9299c3e9 MCC |
341 | of the base 2.6.12 kernel source. |
342 | ||
754c7976 JJ |
343 | So, in order to apply the 2.6.12.3 patch to your existing 2.6.12.2 kernel |
344 | source you have to first back out the 2.6.12.2 patch (so you are left with a | |
345 | base 2.6.12 kernel source) and then apply the new 2.6.12.3 patch. | |
346 | ||
347 | Here's a small example: | |
348 | ||
9299c3e9 | 349 | :: |
754c7976 | 350 | |
9299c3e9 MCC |
351 | $ cd ~/linux-2.6.12.2 # change to the kernel source dir |
352 | $ patch -p1 -R < ../patch-2.6.12.2 # revert the 2.6.12.2 patch | |
353 | $ patch -p1 < ../patch-2.6.12.3 # apply the new 2.6.12.3 patch | |
354 | $ cd .. | |
355 | $ mv linux-2.6.12.2 linux-2.6.12.3 # rename the kernel source dir | |
754c7976 JJ |
356 | |
357 | The -rc kernels | |
9299c3e9 MCC |
358 | =============== |
359 | ||
360 | These are release-candidate kernels. These are development kernels released | |
754c7976 JJ |
361 | by Linus whenever he deems the current git (the kernel's source management |
362 | tool) tree to be in a reasonably sane state adequate for testing. | |
363 | ||
364 | These kernels are not stable and you should expect occasional breakage if | |
365 | you intend to run them. This is however the most stable of the main | |
366 | development branches and is also what will eventually turn into the next | |
367 | stable kernel, so it is important that it be tested by as many people as | |
368 | possible. | |
369 | ||
370 | This is a good branch to run for people who want to help out testing | |
371 | development kernels but do not want to run some of the really experimental | |
372 | stuff (such people should see the sections about -git and -mm kernels below). | |
373 | ||
374 | The -rc patches are not incremental, they apply to a base 2.6.x kernel, just | |
375 | like the 2.6.x.y patches described above. The kernel version before the -rcN | |
376 | suffix denotes the version of the kernel that this -rc kernel will eventually | |
377 | turn into. | |
9299c3e9 | 378 | |
754c7976 JJ |
379 | So, 2.6.13-rc5 means that this is the fifth release candidate for the 2.6.13 |
380 | kernel and the patch should be applied on top of the 2.6.12 kernel source. | |
381 | ||
382 | Here are 3 examples of how to apply these patches: | |
383 | ||
9299c3e9 MCC |
384 | :: |
385 | ||
386 | # first an example of moving from 2.6.12 to 2.6.13-rc3 | |
387 | $ cd ~/linux-2.6.12 # change to the 2.6.12 source dir | |
388 | $ patch -p1 < ../patch-2.6.13-rc3 # apply the 2.6.13-rc3 patch | |
389 | $ cd .. | |
390 | $ mv linux-2.6.12 linux-2.6.13-rc3 # rename the source dir | |
754c7976 | 391 | |
9299c3e9 MCC |
392 | # now let's move from 2.6.13-rc3 to 2.6.13-rc5 |
393 | $ cd ~/linux-2.6.13-rc3 # change to the 2.6.13-rc3 dir | |
394 | $ patch -p1 -R < ../patch-2.6.13-rc3 # revert the 2.6.13-rc3 patch | |
395 | $ patch -p1 < ../patch-2.6.13-rc5 # apply the new 2.6.13-rc5 patch | |
396 | $ cd .. | |
397 | $ mv linux-2.6.13-rc3 linux-2.6.13-rc5 # rename the source dir | |
754c7976 | 398 | |
9299c3e9 MCC |
399 | # finally let's try and move from 2.6.12.3 to 2.6.13-rc5 |
400 | $ cd ~/linux-2.6.12.3 # change to the kernel source dir | |
401 | $ patch -p1 -R < ../patch-2.6.12.3 # revert the 2.6.12.3 patch | |
402 | $ patch -p1 < ../patch-2.6.13-rc5 # apply new 2.6.13-rc5 patch | |
403 | $ cd .. | |
404 | $ mv linux-2.6.12.3 linux-2.6.13-rc5 # rename the kernel source dir | |
754c7976 JJ |
405 | |
406 | ||
407 | The -git kernels | |
9299c3e9 MCC |
408 | ================ |
409 | ||
410 | These are daily snapshots of Linus' kernel tree (managed in a git | |
754c7976 JJ |
411 | repository, hence the name). |
412 | ||
413 | These patches are usually released daily and represent the current state of | |
c594a50d | 414 | Linus's tree. They are more experimental than -rc kernels since they are |
754c7976 JJ |
415 | generated automatically without even a cursory glance to see if they are |
416 | sane. | |
417 | ||
418 | -git patches are not incremental and apply either to a base 2.6.x kernel or | |
c594a50d | 419 | a base 2.6.x-rc kernel -- you can see which from their name. |
754c7976 JJ |
420 | A patch named 2.6.12-git1 applies to the 2.6.12 kernel source and a patch |
421 | named 2.6.13-rc3-git2 applies to the source of the 2.6.13-rc3 kernel. | |
422 | ||
423 | Here are some examples of how to apply these patches: | |
424 | ||
9299c3e9 | 425 | :: |
754c7976 | 426 | |
9299c3e9 MCC |
427 | # moving from 2.6.12 to 2.6.12-git1 |
428 | $ cd ~/linux-2.6.12 # change to the kernel source dir | |
429 | $ patch -p1 < ../patch-2.6.12-git1 # apply the 2.6.12-git1 patch | |
430 | $ cd .. | |
431 | $ mv linux-2.6.12 linux-2.6.12-git1 # rename the kernel source dir | |
432 | ||
433 | # moving from 2.6.12-git1 to 2.6.13-rc2-git3 | |
434 | $ cd ~/linux-2.6.12-git1 # change to the kernel source dir | |
435 | $ patch -p1 -R < ../patch-2.6.12-git1 # revert the 2.6.12-git1 patch | |
436 | # we now have a 2.6.12 kernel | |
437 | $ patch -p1 < ../patch-2.6.13-rc2 # apply the 2.6.13-rc2 patch | |
438 | # the kernel is now 2.6.13-rc2 | |
439 | $ patch -p1 < ../patch-2.6.13-rc2-git3 # apply the 2.6.13-rc2-git3 patch | |
440 | # the kernel is now 2.6.13-rc2-git3 | |
441 | $ cd .. | |
442 | $ mv linux-2.6.12-git1 linux-2.6.13-rc2-git3 # rename source dir | |
754c7976 JJ |
443 | |
444 | ||
445 | The -mm kernels | |
9299c3e9 MCC |
446 | =============== |
447 | ||
448 | These are experimental kernels released by Andrew Morton. | |
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449 | |
450 | The -mm tree serves as a sort of proving ground for new features and other | |
451 | experimental patches. | |
9299c3e9 | 452 | |
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453 | Once a patch has proved its worth in -mm for a while Andrew pushes it on to |
454 | Linus for inclusion in mainline. | |
455 | ||
456 | Although it's encouraged that patches flow to Linus via the -mm tree, this | |
457 | is not always enforced. | |
9299c3e9 | 458 | |
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459 | Subsystem maintainers (or individuals) sometimes push their patches directly |
460 | to Linus, even though (or after) they have been merged and tested in -mm (or | |
461 | sometimes even without prior testing in -mm). | |
462 | ||
463 | You should generally strive to get your patches into mainline via -mm to | |
464 | ensure maximum testing. | |
465 | ||
466 | This branch is in constant flux and contains many experimental features, a | |
c594a50d | 467 | lot of debugging patches not appropriate for mainline etc., and is the most |
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468 | experimental of the branches described in this document. |
469 | ||
470 | These kernels are not appropriate for use on systems that are supposed to be | |
471 | stable and they are more risky to run than any of the other branches (make | |
c594a50d | 472 | sure you have up-to-date backups -- that goes for any experimental kernel but |
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473 | even more so for -mm kernels). |
474 | ||
475 | These kernels in addition to all the other experimental patches they contain | |
476 | usually also contain any changes in the mainline -git kernels available at | |
477 | the time of release. | |
478 | ||
479 | Testing of -mm kernels is greatly appreciated since the whole point of the | |
480 | tree is to weed out regressions, crashes, data corruption bugs, build | |
481 | breakage (and any other bug in general) before changes are merged into the | |
482 | more stable mainline Linus tree. | |
9299c3e9 | 483 | |
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484 | But testers of -mm should be aware that breakage in this tree is more common |
485 | than in any other tree. | |
486 | ||
487 | The -mm kernels are not released on a fixed schedule, but usually a few -mm | |
488 | kernels are released in between each -rc kernel (1 to 3 is common). | |
9299c3e9 | 489 | |
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490 | The -mm kernels apply to either a base 2.6.x kernel (when no -rc kernels |
491 | have been released yet) or to a Linus -rc kernel. | |
492 | ||
493 | Here are some examples of applying the -mm patches: | |
494 | ||
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495 | :: |
496 | ||
497 | # moving from 2.6.12 to 2.6.12-mm1 | |
498 | $ cd ~/linux-2.6.12 # change to the 2.6.12 source dir | |
499 | $ patch -p1 < ../2.6.12-mm1 # apply the 2.6.12-mm1 patch | |
500 | $ cd .. | |
501 | $ mv linux-2.6.12 linux-2.6.12-mm1 # rename the source appropriately | |
502 | ||
503 | # moving from 2.6.12-mm1 to 2.6.13-rc3-mm3 | |
504 | $ cd ~/linux-2.6.12-mm1 | |
505 | $ patch -p1 -R < ../2.6.12-mm1 # revert the 2.6.12-mm1 patch | |
506 | # we now have a 2.6.12 source | |
507 | $ patch -p1 < ../patch-2.6.13-rc3 # apply the 2.6.13-rc3 patch | |
508 | # we now have a 2.6.13-rc3 source | |
509 | $ patch -p1 < ../2.6.13-rc3-mm3 # apply the 2.6.13-rc3-mm3 patch | |
510 | $ cd .. | |
511 | $ mv linux-2.6.12-mm1 linux-2.6.13-rc3-mm3 # rename the source dir | |
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512 | |
513 | ||
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514 | This concludes this list of explanations of the various kernel trees. |
515 | I hope you are now clear on how to apply the various patches and help testing | |
516 | the kernel. | |
517 | ||
518 | Thank you's to Randy Dunlap, Rolf Eike Beer, Linus Torvalds, Bodo Eggert, | |
519 | Johannes Stezenbach, Grant Coady, Pavel Machek and others that I may have | |
520 | forgotten for their reviews and contributions to this document. | |
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