1.. _stable_kernel_rules: 2 3Everything you ever wanted to know about Linux -stable releases 4=============================================================== 5 6Rules on what kind of patches are accepted, and which ones are not, into the 7"-stable" tree: 8 9 - It must be obviously correct and tested. 10 - It cannot be bigger than 100 lines, with context. 11 - It must fix only one thing. 12 - It must fix a real bug that bothers people (not a, "This could be a 13 problem..." type thing). 14 - It must fix a problem that causes a build error (but not for things 15 marked CONFIG_BROKEN), an oops, a hang, data corruption, a real 16 security issue, or some "oh, that's not good" issue. In short, something 17 critical. 18 - Serious issues as reported by a user of a distribution kernel may also 19 be considered if they fix a notable performance or interactivity issue. 20 As these fixes are not as obvious and have a higher risk of a subtle 21 regression they should only be submitted by a distribution kernel 22 maintainer and include an addendum linking to a bugzilla entry if it 23 exists and additional information on the user-visible impact. 24 - New device IDs and quirks are also accepted. 25 - No "theoretical race condition" issues, unless an explanation of how the 26 race can be exploited is also provided. 27 - It cannot contain any "trivial" fixes in it (spelling changes, 28 whitespace cleanups, etc). 29 - It must follow the 30 :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` 31 rules. 32 - It or an equivalent fix must already exist in Linus' tree (upstream). 33 34 35Procedure for submitting patches to the -stable tree 36---------------------------------------------------- 37 38 - Security patches should not be handled (solely) by the -stable review 39 process but should follow the procedures in 40 :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>`. 41 42For all other submissions, choose one of the following procedures 43----------------------------------------------------------------- 44 45.. _option_1: 46 47Option 1 48******** 49 50To have the patch automatically included in the stable tree, add the tag 51 52.. code-block:: none 53 54 Cc: stable@vger.kernel.org 55 56in the sign-off area. Once the patch is merged it will be applied to 57the stable tree without anything else needing to be done by the author 58or subsystem maintainer. 59 60.. _option_2: 61 62Option 2 63******** 64 65After the patch has been merged to Linus' tree, send an email to 66stable@vger.kernel.org containing the subject of the patch, the commit ID, 67why you think it should be applied, and what kernel version you wish it to 68be applied to. 69 70.. _option_3: 71 72Option 3 73******** 74 75Send the patch, after verifying that it follows the above rules, to 76stable@vger.kernel.org. You must note the upstream commit ID in the 77changelog of your submission, as well as the kernel version you wish 78it to be applied to. 79 80:ref:`option_1` is **strongly** preferred, is the easiest and most common. 81:ref:`option_2` and :ref:`option_3` are more useful if the patch isn't deemed 82worthy at the time it is applied to a public git tree (for instance, because 83it deserves more regression testing first). :ref:`option_3` is especially 84useful if the patch needs some special handling to apply to an older kernel 85(e.g., if API's have changed in the meantime). 86 87Note that for :ref:`option_3`, if the patch deviates from the original 88upstream patch (for example because it had to be backported) this must be very 89clearly documented and justified in the patch description. 90 91The upstream commit ID must be specified with a separate line above the commit 92text, like this: 93 94.. code-block:: none 95 96 commit <sha1> upstream. 97 98Additionally, some patches submitted via :ref:`option_1` may have additional 99patch prerequisites which can be cherry-picked. This can be specified in the 100following format in the sign-off area: 101 102.. code-block:: none 103 104 Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle 105 Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle 106 Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic 107 Cc: <stable@vger.kernel.org> # 3.3.x 108 Signed-off-by: Ingo Molnar <mingo@elte.hu> 109 110The tag sequence has the meaning of: 111 112.. code-block:: none 113 114 git cherry-pick a1f84a3 115 git cherry-pick 1b9508f 116 git cherry-pick fd21073 117 git cherry-pick <this commit> 118 119Also, some patches may have kernel version prerequisites. This can be 120specified in the following format in the sign-off area: 121 122.. code-block:: none 123 124 Cc: <stable@vger.kernel.org> # 3.3.x 125 126The tag has the meaning of: 127 128.. code-block:: none 129 130 git cherry-pick <this commit> 131 132For each "-stable" tree starting with the specified version. 133 134Following the submission: 135 136 - The sender will receive an ACK when the patch has been accepted into the 137 queue, or a NAK if the patch is rejected. This response might take a few 138 days, according to the developer's schedules. 139 - If accepted, the patch will be added to the -stable queue, for review by 140 other developers and by the relevant subsystem maintainer. 141 142 143Review cycle 144------------ 145 146 - When the -stable maintainers decide for a review cycle, the patches will be 147 sent to the review committee, and the maintainer of the affected area of 148 the patch (unless the submitter is the maintainer of the area) and CC: to 149 the linux-kernel mailing list. 150 - The review committee has 48 hours in which to ACK or NAK the patch. 151 - If the patch is rejected by a member of the committee, or linux-kernel 152 members object to the patch, bringing up issues that the maintainers and 153 members did not realize, the patch will be dropped from the queue. 154 - At the end of the review cycle, the ACKed patches will be added to the 155 latest -stable release, and a new -stable release will happen. 156 - Security patches will be accepted into the -stable tree directly from the 157 security kernel team, and not go through the normal review cycle. 158 Contact the kernel security team for more details on this procedure. 159 160Trees 161----- 162 163 - The queues of patches, for both completed versions and in progress 164 versions can be found at: 165 166 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git 167 168 - The finalized and tagged releases of all stable kernels can be found 169 in separate branches per version at: 170 171 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git 172 173 174Review committee 175---------------- 176 177 - This is made up of a number of kernel developers who have volunteered for 178 this task, and a few that haven't. 179