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 after first checking the stable networking queue at 42 https://patchwork.ozlabs.org/bundle/davem/stable/?series=&submitter=&state=*&q=&archive= 43 to ensure the requested patch is not already queued up. 44 - Security patches should not be handled (solely) by the -stable review 45 process but should follow the procedures in 46 :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>`. 47 48For all other submissions, choose one of the following procedures 49----------------------------------------------------------------- 50 51.. _option_1: 52 53Option 1 54******** 55 56To have the patch automatically included in the stable tree, add the tag 57 58.. code-block:: none 59 60 Cc: stable@vger.kernel.org 61 62in the sign-off area. Once the patch is merged it will be applied to 63the stable tree without anything else needing to be done by the author 64or subsystem maintainer. 65 66.. _option_2: 67 68Option 2 69******** 70 71After the patch has been merged to Linus' tree, send an email to 72stable@vger.kernel.org containing the subject of the patch, the commit ID, 73why you think it should be applied, and what kernel version you wish it to 74be applied to. 75 76.. _option_3: 77 78Option 3 79******** 80 81Send the patch, after verifying that it follows the above rules, to 82stable@vger.kernel.org. You must note the upstream commit ID in the 83changelog of your submission, as well as the kernel version you wish 84it to be applied to. 85 86:ref:`option_1` is **strongly** preferred, is the easiest and most common. 87:ref:`option_2` and :ref:`option_3` are more useful if the patch isn't deemed 88worthy at the time it is applied to a public git tree (for instance, because 89it deserves more regression testing first). :ref:`option_3` is especially 90useful if the patch needs some special handling to apply to an older kernel 91(e.g., if API's have changed in the meantime). 92 93Note that for :ref:`option_3`, if the patch deviates from the original 94upstream patch (for example because it had to be backported) this must be very 95clearly documented and justified in the patch description. 96 97The upstream commit ID must be specified with a separate line above the commit 98text, like this: 99 100.. code-block:: none 101 102 commit <sha1> upstream. 103 104Additionally, some patches submitted via :ref:`option_1` may have additional 105patch prerequisites which can be cherry-picked. This can be specified in the 106following format in the sign-off area: 107 108.. code-block:: none 109 110 Cc: <stable@vger.kernel.org> # 3.3.x: a1f84a3: sched: Check for idle 111 Cc: <stable@vger.kernel.org> # 3.3.x: 1b9508f: sched: Rate-limit newidle 112 Cc: <stable@vger.kernel.org> # 3.3.x: fd21073: sched: Fix affinity logic 113 Cc: <stable@vger.kernel.org> # 3.3.x 114 Signed-off-by: Ingo Molnar <mingo@elte.hu> 115 116The tag sequence has the meaning of: 117 118.. code-block:: none 119 120 git cherry-pick a1f84a3 121 git cherry-pick 1b9508f 122 git cherry-pick fd21073 123 git cherry-pick <this commit> 124 125Also, some patches may have kernel version prerequisites. This can be 126specified in the following format in the sign-off area: 127 128.. code-block:: none 129 130 Cc: <stable@vger.kernel.org> # 3.3.x 131 132The tag has the meaning of: 133 134.. code-block:: none 135 136 git cherry-pick <this commit> 137 138For each "-stable" tree starting with the specified version. 139 140Following the submission: 141 142 - The sender will receive an ACK when the patch has been accepted into the 143 queue, or a NAK if the patch is rejected. This response might take a few 144 days, according to the developer's schedules. 145 - If accepted, the patch will be added to the -stable queue, for review by 146 other developers and by the relevant subsystem maintainer. 147 148 149Review cycle 150------------ 151 152 - When the -stable maintainers decide for a review cycle, the patches will be 153 sent to the review committee, and the maintainer of the affected area of 154 the patch (unless the submitter is the maintainer of the area) and CC: to 155 the linux-kernel mailing list. 156 - The review committee has 48 hours in which to ACK or NAK the patch. 157 - If the patch is rejected by a member of the committee, or linux-kernel 158 members object to the patch, bringing up issues that the maintainers and 159 members did not realize, the patch will be dropped from the queue. 160 - At the end of the review cycle, the ACKed patches will be added to the 161 latest -stable release, and a new -stable release will happen. 162 - Security patches will be accepted into the -stable tree directly from the 163 security kernel team, and not go through the normal review cycle. 164 Contact the kernel security team for more details on this procedure. 165 166Trees 167----- 168 169 - The queues of patches, for both completed versions and in progress 170 versions can be found at: 171 172 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git 173 174 - The finalized and tagged releases of all stable kernels can be found 175 in separate branches per version at: 176 177 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git 178 179 180Review committee 181---------------- 182 183 - This is made up of a number of kernel developers who have volunteered for 184 this task, and a few that haven't. 185