| 1 | .. _submitchecklist:
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| 2 |
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| 3 | =======================================
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| 4 | Linux Kernel patch submission checklist
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| 5 | =======================================
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| 6 |
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| 7 | Here are some basic things that developers should do if they want to see their
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| 8 | kernel patch submissions accepted more quickly.
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| 9 |
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| 10 | These are all above and beyond the documentation that is provided in
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| 11 | :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`
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| 12 | and elsewhere regarding submitting Linux kernel patches.
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| 13 |
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| 14 | Review your code
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| 15 | ================
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| 16 |
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| 17 | 1) If you use a facility then #include the file that defines/declares
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| 18 | that facility. Don't depend on other header files pulling in ones
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| 19 | that you use.
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| 20 |
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| 21 | 2) Check your patch for general style as detailed in
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| 22 | :ref:`Documentation/process/coding-style.rst <codingstyle>`.
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| 23 |
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| 24 | 3) All memory barriers {e.g., ``barrier()``, ``rmb()``, ``wmb()``} need a
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| 25 | comment in the source code that explains the logic of what they are doing
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| 26 | and why.
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| 27 |
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| 28 | Review Kconfig changes
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| 29 | ======================
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| 30 |
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| 31 | 1) Any new or modified ``CONFIG`` options do not muck up the config menu and
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| 32 | default to off unless they meet the exception criteria documented in
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| 33 | ``Documentation/kbuild/kconfig-language.rst`` Menu attributes: default value.
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| 34 |
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| 35 | 2) All new ``Kconfig`` options have help text.
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| 36 |
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| 37 | 3) Has been carefully reviewed with respect to relevant ``Kconfig``
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| 38 | combinations. This is very hard to get right with testing---brainpower
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| 39 | pays off here.
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| 40 |
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| 41 | Provide documentation
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| 42 | =====================
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| 43 |
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| 44 | 1) Include :ref:`kernel-doc <kernel_doc>` to document global kernel APIs.
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| 45 | (Not required for static functions, but OK there also.)
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| 46 |
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| 47 | 2) All new ``/proc`` entries are documented under ``Documentation/``
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| 48 |
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| 49 | 3) All new kernel boot parameters are documented in
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| 50 | ``Documentation/admin-guide/kernel-parameters.rst``.
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| 51 |
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| 52 | 4) All new module parameters are documented with ``MODULE_PARM_DESC()``
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| 53 |
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| 54 | 5) All new userspace interfaces are documented in ``Documentation/ABI/``.
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| 55 | See Documentation/admin-guide/abi.rst (or ``Documentation/ABI/README``)
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| 56 | for more information.
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| 57 | Patches that change userspace interfaces should be CCed to
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| 58 | [email protected].
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| 59 |
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| 60 | 6) If any ioctl's are added by the patch, then also update
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| 61 | ``Documentation/userspace-api/ioctl/ioctl-number.rst``.
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| 62 |
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| 63 | Check your code with tools
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| 64 | ==========================
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| 65 |
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| 66 | 1) Check for trivial violations with the patch style checker prior to
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| 67 | submission (``scripts/checkpatch.pl``).
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| 68 | You should be able to justify all violations that remain in
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| 69 | your patch.
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| 70 |
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| 71 | 2) Check cleanly with sparse.
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| 72 |
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| 73 | 3) Use ``make checkstack`` and fix any problems that it finds.
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| 74 | Note that ``checkstack`` does not point out problems explicitly,
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| 75 | but any one function that uses more than 512 bytes on the stack is a
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| 76 | candidate for change.
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| 77 |
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| 78 | Build your code
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| 79 | ===============
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| 80 |
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| 81 | 1) Builds cleanly:
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| 82 |
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| 83 | a) with applicable or modified ``CONFIG`` options ``=y``, ``=m``, and
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| 84 | ``=n``. No ``gcc`` warnings/errors, no linker warnings/errors.
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| 85 |
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| 86 | b) Passes ``allnoconfig``, ``allmodconfig``
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| 87 |
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| 88 | c) Builds successfully when using ``O=builddir``
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| 89 |
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| 90 | d) Any Documentation/ changes build successfully without new warnings/errors.
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| 91 | Use ``make htmldocs`` or ``make pdfdocs`` to check the build and
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| 92 | fix any issues.
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| 93 |
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| 94 | 2) Builds on multiple CPU architectures by using local cross-compile tools
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| 95 | or some other build farm.
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| 96 | Note that testing against architectures of different word sizes
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| 97 | (32- and 64-bit) and different endianness (big- and little-) is effective
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| 98 | in catching various portability issues due to false assumptions on
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| 99 | representable quantity range, data alignment, or endianness, among
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| 100 | others.
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| 101 |
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| 102 | 3) Newly-added code has been compiled with ``gcc -W`` (use
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| 103 | ``make KCFLAGS=-W``). This will generate lots of noise, but is good
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| 104 | for finding bugs like "warning: comparison between signed and unsigned".
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| 105 |
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| 106 | 4) If your modified source code depends on or uses any of the kernel
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| 107 | APIs or features that are related to the following ``Kconfig`` symbols,
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| 108 | then test multiple builds with the related ``Kconfig`` symbols disabled
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| 109 | and/or ``=m`` (if that option is available) [not all of these at the
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| 110 | same time, just various/random combinations of them]:
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| 111 |
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| 112 | ``CONFIG_SMP``, ``CONFIG_SYSFS``, ``CONFIG_PROC_FS``, ``CONFIG_INPUT``,
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| 113 | ``CONFIG_PCI``, ``CONFIG_BLOCK``, ``CONFIG_PM``, ``CONFIG_MAGIC_SYSRQ``,
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| 114 | ``CONFIG_NET``, ``CONFIG_INET=n`` (but latter with ``CONFIG_NET=y``).
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| 115 |
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| 116 | Test your code
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| 117 | ==============
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| 118 |
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| 119 | 1) Has been tested with ``CONFIG_PREEMPT``, ``CONFIG_DEBUG_PREEMPT``,
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| 120 | ``CONFIG_SLUB_DEBUG``, ``CONFIG_DEBUG_PAGEALLOC``, ``CONFIG_DEBUG_MUTEXES``,
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| 121 | ``CONFIG_DEBUG_SPINLOCK``, ``CONFIG_DEBUG_ATOMIC_SLEEP``,
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| 122 | ``CONFIG_PROVE_RCU`` and ``CONFIG_DEBUG_OBJECTS_RCU_HEAD`` all
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| 123 | simultaneously enabled.
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| 124 |
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| 125 | 2) Has been build- and runtime tested with and without ``CONFIG_SMP`` and
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| 126 | ``CONFIG_PREEMPT.``
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| 127 |
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| 128 | 3) All codepaths have been exercised with all lockdep features enabled.
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| 129 |
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| 130 | 4) Has been checked with injection of at least slab and page-allocation
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| 131 | failures. See ``Documentation/fault-injection/``.
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| 132 | If the new code is substantial, addition of subsystem-specific fault
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| 133 | injection might be appropriate.
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| 134 |
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| 135 | 5) Tested with the most recent tag of linux-next to make sure that it still
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| 136 | works with all of the other queued patches and various changes in the VM,
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| 137 | VFS, and other subsystems.
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