stable-kernel-rules.rst 6.8 KB

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  1. .. _stable_kernel_rules:
  2. Everything you ever wanted to know about Linux -stable releases
  3. ===============================================================
  4. Rules on what kind of patches are accepted, and which ones are not, into the
  5. "-stable" tree:
  6. - It must be obviously correct and tested.
  7. - It cannot be bigger than 100 lines, with context.
  8. - It must fix only one thing.
  9. - It must fix a real bug that bothers people (not a, "This could be a
  10. problem..." type thing).
  11. - It must fix a problem that causes a build error (but not for things
  12. marked CONFIG_BROKEN), an oops, a hang, data corruption, a real
  13. security issue, or some "oh, that's not good" issue. In short, something
  14. critical.
  15. - Serious issues as reported by a user of a distribution kernel may also
  16. be considered if they fix a notable performance or interactivity issue.
  17. As these fixes are not as obvious and have a higher risk of a subtle
  18. regression they should only be submitted by a distribution kernel
  19. maintainer and include an addendum linking to a bugzilla entry if it
  20. exists and additional information on the user-visible impact.
  21. - New device IDs and quirks are also accepted.
  22. - No "theoretical race condition" issues, unless an explanation of how the
  23. race can be exploited is also provided.
  24. - It cannot contain any "trivial" fixes in it (spelling changes,
  25. whitespace cleanups, etc).
  26. - It must follow the
  27. :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`
  28. rules.
  29. - It or an equivalent fix must already exist in Linus' tree (upstream).
  30. Procedure for submitting patches to the -stable tree
  31. ----------------------------------------------------
  32. - Security patches should not be handled (solely) by the -stable review
  33. process but should follow the procedures in
  34. :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>`.
  35. For all other submissions, choose one of the following procedures
  36. -----------------------------------------------------------------
  37. .. _option_1:
  38. Option 1
  39. ********
  40. To have the patch automatically included in the stable tree, add the tag
  41. .. code-block:: none
  42. Cc: stable@vger.kernel.org
  43. in the sign-off area. Once the patch is merged it will be applied to
  44. the stable tree without anything else needing to be done by the author
  45. or subsystem maintainer.
  46. .. _option_2:
  47. Option 2
  48. ********
  49. After the patch has been merged to Linus' tree, send an email to
  50. stable@vger.kernel.org containing the subject of the patch, the commit ID,
  51. why you think it should be applied, and what kernel version you wish it to
  52. be applied to.
  53. .. _option_3:
  54. Option 3
  55. ********
  56. Send the patch, after verifying that it follows the above rules, to
  57. stable@vger.kernel.org. You must note the upstream commit ID in the
  58. changelog of your submission, as well as the kernel version you wish
  59. it to be applied to.
  60. :ref:`option_1` is **strongly** preferred, is the easiest and most common.
  61. :ref:`option_2` and :ref:`option_3` are more useful if the patch isn't deemed
  62. worthy at the time it is applied to a public git tree (for instance, because
  63. it deserves more regression testing first). :ref:`option_3` is especially
  64. useful if the patch needs some special handling to apply to an older kernel
  65. (e.g., if API's have changed in the meantime).
  66. Note that for :ref:`option_3`, if the patch deviates from the original
  67. upstream patch (for example because it had to be backported) this must be very
  68. clearly documented and justified in the patch description.
  69. The upstream commit ID must be specified with a separate line above the commit
  70. text, like this:
  71. .. code-block:: none
  72. commit <sha1> upstream.
  73. Additionally, some patches submitted via :ref:`option_1` may have additional
  74. patch prerequisites which can be cherry-picked. This can be specified in the
  75. following format in the sign-off area:
  76. .. code-block:: none
  77. Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle
  78. Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle
  79. Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic
  80. Cc: <stable@vger.kernel.org> # 3.3.x
  81. Signed-off-by: Ingo Molnar <mingo@elte.hu>
  82. The tag sequence has the meaning of:
  83. .. code-block:: none
  84. git cherry-pick a1f84a3
  85. git cherry-pick 1b9508f
  86. git cherry-pick fd21073
  87. git cherry-pick <this commit>
  88. Also, some patches may have kernel version prerequisites. This can be
  89. specified in the following format in the sign-off area:
  90. .. code-block:: none
  91. Cc: <stable@vger.kernel.org> # 3.3.x
  92. The tag has the meaning of:
  93. .. code-block:: none
  94. git cherry-pick <this commit>
  95. For each "-stable" tree starting with the specified version.
  96. Following the submission:
  97. - The sender will receive an ACK when the patch has been accepted into the
  98. queue, or a NAK if the patch is rejected. This response might take a few
  99. days, according to the developer's schedules.
  100. - If accepted, the patch will be added to the -stable queue, for review by
  101. other developers and by the relevant subsystem maintainer.
  102. Review cycle
  103. ------------
  104. - When the -stable maintainers decide for a review cycle, the patches will be
  105. sent to the review committee, and the maintainer of the affected area of
  106. the patch (unless the submitter is the maintainer of the area) and CC: to
  107. the linux-kernel mailing list.
  108. - The review committee has 48 hours in which to ACK or NAK the patch.
  109. - If the patch is rejected by a member of the committee, or linux-kernel
  110. members object to the patch, bringing up issues that the maintainers and
  111. members did not realize, the patch will be dropped from the queue.
  112. - At the end of the review cycle, the ACKed patches will be added to the
  113. latest -stable release, and a new -stable release will happen.
  114. - Security patches will be accepted into the -stable tree directly from the
  115. security kernel team, and not go through the normal review cycle.
  116. Contact the kernel security team for more details on this procedure.
  117. Trees
  118. -----
  119. - The queues of patches, for both completed versions and in progress
  120. versions can be found at:
  121. https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git
  122. - The finalized and tagged releases of all stable kernels can be found
  123. in separate branches per version at:
  124. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
  125. - The release candidate of all stable kernel versions can be found at:
  126. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/
  127. .. warning::
  128. The -stable-rc tree is a snapshot in time of the stable-queue tree and
  129. will change frequently, hence will be rebased often. It should only be
  130. used for testing purposes (e.g. to be consumed by CI systems).
  131. Review committee
  132. ----------------
  133. - This is made up of a number of kernel developers who have volunteered for
  134. this task, and a few that haven't.