174 lines
7.3 KiB
Text
174 lines
7.3 KiB
Text
Background
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==========
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The upstream Linux kernel maintainers only fix bugs for specific kernel
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versions. Those versions include the current "release candidate" (or -rc)
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kernel, any "stable" kernel versions, and any "long term" kernels.
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Please see https://www.kernel.org/ for a list of supported kernels. Any
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kernel marked with [EOL] is "end of life" and will not have any fixes
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backported to it.
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If you've found a bug on a kernel version that isn't listed on kernel.org,
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contact your Linux distribution or embedded vendor for support.
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Alternatively, you can attempt to run one of the supported stable or -rc
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kernels, and see if you can reproduce the bug on that. It's preferable
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to reproduce the bug on the latest -rc kernel.
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How to report Linux kernel bugs
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===============================
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Identify the problematic subsystem
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----------------------------------
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Identifying which part of the Linux kernel might be causing your issue
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increases your chances of getting your bug fixed. Simply posting to the
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generic linux-kernel mailing list (LKML) may cause your bug report to be
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lost in the noise of a mailing list that gets 1000+ emails a day.
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Instead, try to figure out which kernel subsystem is causing the issue,
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and email that subsystem's maintainer and mailing list. If the subsystem
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maintainer doesn't answer, then expand your scope to mailing lists like
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LKML.
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Identify who to notify
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----------------------
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Once you know the subsystem that is causing the issue, you should send a
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bug report. Some maintainers prefer bugs to be reported via bugzilla
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(https://bugzilla.kernel.org), while others prefer that bugs be reported
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via the subsystem mailing list.
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To find out where to send an emailed bug report, find your subsystem or
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device driver in the MAINTAINERS file. Search in the file for relevant
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entries, and send your bug report to the person(s) listed in the "M:"
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lines, making sure to Cc the mailing list(s) in the "L:" lines. When the
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maintainer replies to you, make sure to 'Reply-all' in order to keep the
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public mailing list(s) in the email thread.
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If you know which driver is causing issues, you can pass one of the driver
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files to the get_maintainer.pl script:
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perl scripts/get_maintainer.pl -f <filename>
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If it is a security bug, please copy the Security Contact listed in the
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MAINTAINERS file. They can help coordinate bugfix and disclosure. See
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Documentation/SecurityBugs for more information.
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If you can't figure out which subsystem caused the issue, you should file
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a bug in kernel.org bugzilla and send email to
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linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more
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information on the linux-kernel mailing list see
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http://www.tux.org/lkml/).
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Tips for reporting bugs
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-----------------------
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If you haven't reported a bug before, please read:
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http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
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http://www.catb.org/esr/faqs/smart-questions.html
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It's REALLY important to report bugs that seem unrelated as separate email
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threads or separate bugzilla entries. If you report several unrelated
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bugs at once, it's difficult for maintainers to tease apart the relevant
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data.
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Gather information
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------------------
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The most important information in a bug report is how to reproduce the
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bug. This includes system information, and (most importantly)
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step-by-step instructions for how a user can trigger the bug.
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If the failure includes an "OOPS:", take a picture of the screen, capture
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a netconsole trace, or type the message from your screen into the bug
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report. Please read "Documentation/oops-tracing.txt" before posting your
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bug report. This explains what you should do with the "Oops" information
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to make it useful to the recipient.
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This is a suggested format for a bug report sent via email or bugzilla.
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Having a standardized bug report form makes it easier for you not to
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overlook things, and easier for the developers to find the pieces of
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information they're really interested in. If some information is not
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relevant to your bug, feel free to exclude it.
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First run the ver_linux script included as scripts/ver_linux, which
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reports the version of some important subsystems. Run this script with
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the command "sh scripts/ver_linux".
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Use that information to fill in all fields of the bug report form, and
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post it to the mailing list with a subject of "PROBLEM: <one line
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summary from [1.]>" for easy identification by the developers.
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[1.] One line summary of the problem:
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[2.] Full description of the problem/report:
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[3.] Keywords (i.e., modules, networking, kernel):
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[4.] Kernel information
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[4.1.] Kernel version (from /proc/version):
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[4.2.] Kernel .config file:
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[5.] Most recent kernel version which did not have the bug:
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[6.] Output of Oops.. message (if applicable) with symbolic information
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resolved (see Documentation/oops-tracing.txt)
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[7.] A small shell script or example program which triggers the
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problem (if possible)
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[8.] Environment
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[8.1.] Software (add the output of the ver_linux script here)
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[8.2.] Processor information (from /proc/cpuinfo):
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[8.3.] Module information (from /proc/modules):
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[8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
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[8.5.] PCI information ('lspci -vvv' as root)
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[8.6.] SCSI information (from /proc/scsi/scsi)
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[8.7.] Other information that might be relevant to the problem
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(please look in /proc and include all information that you
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think to be relevant):
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[X.] Other notes, patches, fixes, workarounds:
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Follow up
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=========
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Expectations for bug reporters
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------------------------------
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Linux kernel maintainers expect bug reporters to be able to follow up on
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bug reports. That may include running new tests, applying patches,
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recompiling your kernel, and/or re-triggering your bug. The most
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frustrating thing for maintainers is for someone to report a bug, and then
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never follow up on a request to try out a fix.
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That said, it's still useful for a kernel maintainer to know a bug exists
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on a supported kernel, even if you can't follow up with retests. Follow
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up reports, such as replying to the email thread with "I tried the latest
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kernel and I can't reproduce my bug anymore" are also helpful, because
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maintainers have to assume silence means things are still broken.
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Expectations for kernel maintainers
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-----------------------------------
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Linux kernel maintainers are busy, overworked human beings. Some times
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they may not be able to address your bug in a day, a week, or two weeks.
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If they don't answer your email, they may be on vacation, or at a Linux
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conference. Check the conference schedule at LWN.net for more info:
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https://lwn.net/Calendar/
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In general, kernel maintainers take 1 to 5 business days to respond to
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bugs. The majority of kernel maintainers are employed to work on the
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kernel, and they may not work on the weekends. Maintainers are scattered
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around the world, and they may not work in your time zone. Unless you
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have a high priority bug, please wait at least a week after the first bug
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report before sending the maintainer a reminder email.
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The exceptions to this rule are regressions, kernel crashes, security holes,
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or userspace breakage caused by new kernel behavior. Those bugs should be
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addressed by the maintainers ASAP. If you suspect a maintainer is not
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responding to these types of bugs in a timely manner (especially during a
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merge window), escalate the bug to LKML and Linus Torvalds.
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Thank you!
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[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ]
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