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 - If the patch covers files in net/ or drivers/net please follow netdev stable 39 submission guidelines as described in 40 :ref:`Documentation/networking/netdev-FAQ.rst <netdev-FAQ>` 41 - Security patches should not be handled (solely) by the -stable review 42 process but should follow the procedures in 43 :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>`. 44 45For all other submissions, choose one of the following procedures 46----------------------------------------------------------------- 47 48.. _option_1: 49 50Option 1 51******** 52 53To have the patch automatically included in the stable tree, add the tag 54 55.. code-block:: none 56 57 Cc: stable@vger.kernel.org 58 59in the sign-off area. Once the patch is merged it will be applied to 60the stable tree without anything else needing to be done by the author 61or subsystem maintainer. 62 63.. _option_2: 64 65Option 2 66******** 67 68After the patch has been merged to Linus' tree, send an email to 69stable@vger.kernel.org containing the subject of the patch, the commit ID, 70why you think it should be applied, and what kernel version you wish it to 71be applied to. 72 73.. _option_3: 74 75Option 3 76******** 77 78Send the patch, after verifying that it follows the above rules, to 79stable@vger.kernel.org. You must note the upstream commit ID in the 80changelog of your submission, as well as the kernel version you wish 81it to be applied to. 82 83:ref:`option_1` is **strongly** preferred, is the easiest and most common. 84:ref:`option_2` and :ref:`option_3` are more useful if the patch isn't deemed 85worthy at the time it is applied to a public git tree (for instance, because 86it deserves more regression testing first). :ref:`option_3` is especially 87useful if the patch needs some special handling to apply to an older kernel 88(e.g., if API's have changed in the meantime). 89 90Note that for :ref:`option_3`, if the patch deviates from the original 91upstream patch (for example because it had to be backported) this must be very 92clearly documented and justified in the patch description. 93 94The upstream commit ID must be specified with a separate line above the commit 95text, like this: 96 97.. code-block:: none 98 99 commit <sha1> upstream. 100 101Additionally, some patches submitted via Option 1 may have additional patch 102prerequisites which can be cherry-picked. This can be specified in the following 103format in the sign-off area: 104 105.. code-block:: none 106 107 Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle 108 Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle 109 Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic 110 Cc: <stable@vger.kernel.org> # 3.3.x 111 Signed-off-by: Ingo Molnar <mingo@elte.hu> 112 113The tag sequence has the meaning of: 114 115.. code-block:: none 116 117 git cherry-pick a1f84a3 118 git cherry-pick 1b9508f 119 git cherry-pick fd21073 120 git cherry-pick <this commit> 121 122Also, some patches may have kernel version prerequisites. This can be 123specified in the following format in the sign-off area: 124 125.. code-block:: none 126 127 Cc: <stable@vger.kernel.org> # 3.3.x 128 129The tag has the meaning of: 130 131.. code-block:: none 132 133 git cherry-pick <this commit> 134 135For each "-stable" tree starting with the specified version. 136 137Following the submission: 138 139 - The sender will receive an ACK when the patch has been accepted into the 140 queue, or a NAK if the patch is rejected. This response might take a few 141 days, according to the developer's schedules. 142 - If accepted, the patch will be added to the -stable queue, for review by 143 other developers and by the relevant subsystem maintainer. 144 145 146Review cycle 147------------ 148 149 - When the -stable maintainers decide for a review cycle, the patches will be 150 sent to the review committee, and the maintainer of the affected area of 151 the patch (unless the submitter is the maintainer of the area) and CC: to 152 the linux-kernel mailing list. 153 - The review committee has 48 hours in which to ACK or NAK the patch. 154 - If the patch is rejected by a member of the committee, or linux-kernel 155 members object to the patch, bringing up issues that the maintainers and 156 members did not realize, the patch will be dropped from the queue. 157 - At the end of the review cycle, the ACKed patches will be added to the 158 latest -stable release, and a new -stable release will happen. 159 - Security patches will be accepted into the -stable tree directly from the 160 security kernel team, and not go through the normal review cycle. 161 Contact the kernel security team for more details on this procedure. 162 163Trees 164----- 165 166 - The queues of patches, for both completed versions and in progress 167 versions can be found at: 168 169 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git 170 171 - The finalized and tagged releases of all stable kernels can be found 172 in separate branches per version at: 173 174 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git 175 176 177Review committee 178---------------- 179 180 - This is made up of a number of kernel developers who have volunteered for 181 this task, and a few that haven't. 182