reporting-bugs.rst 7.5 KB

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  1. .. _reportingbugs:
  2. Reporting bugs
  3. ++++++++++++++
  4. Background
  5. ==========
  6. The upstream Linux kernel maintainers only fix bugs for specific kernel
  7. versions. Those versions include the current "release candidate" (or -rc)
  8. kernel, any "stable" kernel versions, and any "long term" kernels.
  9. Please see https://www.kernel.org/ for a list of supported kernels. Any
  10. kernel marked with [EOL] is "end of life" and will not have any fixes
  11. backported to it.
  12. If you've found a bug on a kernel version that isn't listed on kernel.org,
  13. contact your Linux distribution or embedded vendor for support.
  14. Alternatively, you can attempt to run one of the supported stable or -rc
  15. kernels, and see if you can reproduce the bug on that. It's preferable
  16. to reproduce the bug on the latest -rc kernel.
  17. How to report Linux kernel bugs
  18. ===============================
  19. Identify the problematic subsystem
  20. ----------------------------------
  21. Identifying which part of the Linux kernel might be causing your issue
  22. increases your chances of getting your bug fixed. Simply posting to the
  23. generic linux-kernel mailing list (LKML) may cause your bug report to be
  24. lost in the noise of a mailing list that gets 1000+ emails a day.
  25. Instead, try to figure out which kernel subsystem is causing the issue,
  26. and email that subsystem's maintainer and mailing list. If the subsystem
  27. maintainer doesn't answer, then expand your scope to mailing lists like
  28. LKML.
  29. Identify who to notify
  30. ----------------------
  31. Once you know the subsystem that is causing the issue, you should send a
  32. bug report. Some maintainers prefer bugs to be reported via bugzilla
  33. (https://bugzilla.kernel.org), while others prefer that bugs be reported
  34. via the subsystem mailing list.
  35. To find out where to send an emailed bug report, find your subsystem or
  36. device driver in the MAINTAINERS file. Search in the file for relevant
  37. entries, and send your bug report to the person(s) listed in the "M:"
  38. lines, making sure to Cc the mailing list(s) in the "L:" lines. When the
  39. maintainer replies to you, make sure to 'Reply-all' in order to keep the
  40. public mailing list(s) in the email thread.
  41. If you know which driver is causing issues, you can pass one of the driver
  42. files to the get_maintainer.pl script::
  43. perl scripts/get_maintainer.pl -f <filename>
  44. If it is a security bug, please copy the Security Contact listed in the
  45. MAINTAINERS file. They can help coordinate bugfix and disclosure. See
  46. :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>` for more information.
  47. If you can't figure out which subsystem caused the issue, you should file
  48. a bug in kernel.org bugzilla and send email to
  49. linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more
  50. information on the linux-kernel mailing list see
  51. http://vger.kernel.org/lkml/).
  52. Tips for reporting bugs
  53. -----------------------
  54. If you haven't reported a bug before, please read:
  55. https://www.chiark.greenend.org.uk/~sgtatham/bugs.html
  56. http://www.catb.org/esr/faqs/smart-questions.html
  57. It's REALLY important to report bugs that seem unrelated as separate email
  58. threads or separate bugzilla entries. If you report several unrelated
  59. bugs at once, it's difficult for maintainers to tease apart the relevant
  60. data.
  61. Gather information
  62. ------------------
  63. The most important information in a bug report is how to reproduce the
  64. bug. This includes system information, and (most importantly)
  65. step-by-step instructions for how a user can trigger the bug.
  66. If the failure includes an "OOPS:", take a picture of the screen, capture
  67. a netconsole trace, or type the message from your screen into the bug
  68. report. Please read "Documentation/admin-guide/bug-hunting.rst" before posting your
  69. bug report. This explains what you should do with the "Oops" information
  70. to make it useful to the recipient.
  71. This is a suggested format for a bug report sent via email or bugzilla.
  72. Having a standardized bug report form makes it easier for you not to
  73. overlook things, and easier for the developers to find the pieces of
  74. information they're really interested in. If some information is not
  75. relevant to your bug, feel free to exclude it.
  76. First run the ver_linux script included as scripts/ver_linux, which
  77. reports the version of some important subsystems. Run this script with
  78. the command ``awk -f scripts/ver_linux``.
  79. Use that information to fill in all fields of the bug report form, and
  80. post it to the mailing list with a subject of "PROBLEM: <one line
  81. summary from [1.]>" for easy identification by the developers::
  82. [1.] One line summary of the problem:
  83. [2.] Full description of the problem/report:
  84. [3.] Keywords (i.e., modules, networking, kernel):
  85. [4.] Kernel information
  86. [4.1.] Kernel version (from /proc/version):
  87. [4.2.] Kernel .config file:
  88. [5.] Most recent kernel version which did not have the bug:
  89. [6.] Output of Oops.. message (if applicable) with symbolic information
  90. resolved (see Documentation/admin-guide/bug-hunting.rst)
  91. [7.] A small shell script or example program which triggers the
  92. problem (if possible)
  93. [8.] Environment
  94. [8.1.] Software (add the output of the ver_linux script here)
  95. [8.2.] Processor information (from /proc/cpuinfo):
  96. [8.3.] Module information (from /proc/modules):
  97. [8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
  98. [8.5.] PCI information ('lspci -vvv' as root)
  99. [8.6.] SCSI information (from /proc/scsi/scsi)
  100. [8.7.] Other information that might be relevant to the problem
  101. (please look in /proc and include all information that you
  102. think to be relevant):
  103. [X.] Other notes, patches, fixes, workarounds:
  104. Follow up
  105. =========
  106. Expectations for bug reporters
  107. ------------------------------
  108. Linux kernel maintainers expect bug reporters to be able to follow up on
  109. bug reports. That may include running new tests, applying patches,
  110. recompiling your kernel, and/or re-triggering your bug. The most
  111. frustrating thing for maintainers is for someone to report a bug, and then
  112. never follow up on a request to try out a fix.
  113. That said, it's still useful for a kernel maintainer to know a bug exists
  114. on a supported kernel, even if you can't follow up with retests. Follow
  115. up reports, such as replying to the email thread with "I tried the latest
  116. kernel and I can't reproduce my bug anymore" are also helpful, because
  117. maintainers have to assume silence means things are still broken.
  118. Expectations for kernel maintainers
  119. -----------------------------------
  120. Linux kernel maintainers are busy, overworked human beings. Some times
  121. they may not be able to address your bug in a day, a week, or two weeks.
  122. If they don't answer your email, they may be on vacation, or at a Linux
  123. conference. Check the conference schedule at https://LWN.net for more info:
  124. https://lwn.net/Calendar/
  125. In general, kernel maintainers take 1 to 5 business days to respond to
  126. bugs. The majority of kernel maintainers are employed to work on the
  127. kernel, and they may not work on the weekends. Maintainers are scattered
  128. around the world, and they may not work in your time zone. Unless you
  129. have a high priority bug, please wait at least a week after the first bug
  130. report before sending the maintainer a reminder email.
  131. The exceptions to this rule are regressions, kernel crashes, security holes,
  132. or userspace breakage caused by new kernel behavior. Those bugs should be
  133. addressed by the maintainers ASAP. If you suspect a maintainer is not
  134. responding to these types of bugs in a timely manner (especially during a
  135. merge window), escalate the bug to LKML and Linus Torvalds.
  136. Thank you!
  137. [Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]