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diff --git a/Documentation/admin-guide/reporting-bugs.rst b/Documentation/admin-guide/reporting-bugs.rst new file mode 100644 index 000000000..42481ea7b --- /dev/null +++ b/Documentation/admin-guide/reporting-bugs.rst @@ -0,0 +1,182 @@ +.. _reportingbugs: + +Reporting bugs +++++++++++++++ + +Background +========== + +The upstream Linux kernel maintainers only fix bugs for specific kernel +versions. Those versions include the current "release candidate" (or -rc) +kernel, any "stable" kernel versions, and any "long term" kernels. + +Please see https://www.kernel.org/ for a list of supported kernels. Any +kernel marked with [EOL] is "end of life" and will not have any fixes +backported to it. + +If you've found a bug on a kernel version that isn't listed on kernel.org, +contact your Linux distribution or embedded vendor for support. +Alternatively, you can attempt to run one of the supported stable or -rc +kernels, and see if you can reproduce the bug on that. It's preferable +to reproduce the bug on the latest -rc kernel. + + +How to report Linux kernel bugs +=============================== + + +Identify the problematic subsystem +---------------------------------- + +Identifying which part of the Linux kernel might be causing your issue +increases your chances of getting your bug fixed. Simply posting to the +generic linux-kernel mailing list (LKML) may cause your bug report to be +lost in the noise of a mailing list that gets 1000+ emails a day. + +Instead, try to figure out which kernel subsystem is causing the issue, +and email that subsystem's maintainer and mailing list. If the subsystem +maintainer doesn't answer, then expand your scope to mailing lists like +LKML. + + +Identify who to notify +---------------------- + +Once you know the subsystem that is causing the issue, you should send a +bug report. Some maintainers prefer bugs to be reported via bugzilla +(https://bugzilla.kernel.org), while others prefer that bugs be reported +via the subsystem mailing list. + +To find out where to send an emailed bug report, find your subsystem or +device driver in the MAINTAINERS file. Search in the file for relevant +entries, and send your bug report to the person(s) listed in the "M:" +lines, making sure to Cc the mailing list(s) in the "L:" lines. When the +maintainer replies to you, make sure to 'Reply-all' in order to keep the +public mailing list(s) in the email thread. + +If you know which driver is causing issues, you can pass one of the driver +files to the get_maintainer.pl script:: + + perl scripts/get_maintainer.pl -f <filename> + +If it is a security bug, please copy the Security Contact listed in the +MAINTAINERS file. They can help coordinate bugfix and disclosure. See +:ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>` for more information. + +If you can't figure out which subsystem caused the issue, you should file +a bug in kernel.org bugzilla and send email to +linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more +information on the linux-kernel mailing list see +http://vger.kernel.org/lkml/). + + +Tips for reporting bugs +----------------------- + +If you haven't reported a bug before, please read: + + https://www.chiark.greenend.org.uk/~sgtatham/bugs.html + + http://www.catb.org/esr/faqs/smart-questions.html + +It's REALLY important to report bugs that seem unrelated as separate email +threads or separate bugzilla entries. If you report several unrelated +bugs at once, it's difficult for maintainers to tease apart the relevant +data. + + +Gather information +------------------ + +The most important information in a bug report is how to reproduce the +bug. This includes system information, and (most importantly) +step-by-step instructions for how a user can trigger the bug. + +If the failure includes an "OOPS:", take a picture of the screen, capture +a netconsole trace, or type the message from your screen into the bug +report. Please read "Documentation/admin-guide/bug-hunting.rst" before posting your +bug report. This explains what you should do with the "Oops" information +to make it useful to the recipient. + +This is a suggested format for a bug report sent via email or bugzilla. +Having a standardized bug report form makes it easier for you not to +overlook things, and easier for the developers to find the pieces of +information they're really interested in. If some information is not +relevant to your bug, feel free to exclude it. + +First run the ver_linux script included as scripts/ver_linux, which +reports the version of some important subsystems. Run this script with +the command ``awk -f scripts/ver_linux``. + +Use that information to fill in all fields of the bug report form, and +post it to the mailing list with a subject of "PROBLEM: <one line +summary from [1.]>" for easy identification by the developers:: + + [1.] One line summary of the problem: + [2.] Full description of the problem/report: + [3.] Keywords (i.e., modules, networking, kernel): + [4.] Kernel information + [4.1.] Kernel version (from /proc/version): + [4.2.] Kernel .config file: + [5.] Most recent kernel version which did not have the bug: + [6.] Output of Oops.. message (if applicable) with symbolic information + resolved (see Documentation/admin-guide/bug-hunting.rst) + [7.] A small shell script or example program which triggers the + problem (if possible) + [8.] Environment + [8.1.] Software (add the output of the ver_linux script here) + [8.2.] Processor information (from /proc/cpuinfo): + [8.3.] Module information (from /proc/modules): + [8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem) + [8.5.] PCI information ('lspci -vvv' as root) + [8.6.] SCSI information (from /proc/scsi/scsi) + [8.7.] Other information that might be relevant to the problem + (please look in /proc and include all information that you + think to be relevant): + [X.] Other notes, patches, fixes, workarounds: + + +Follow up +========= + +Expectations for bug reporters +------------------------------ + +Linux kernel maintainers expect bug reporters to be able to follow up on +bug reports. That may include running new tests, applying patches, +recompiling your kernel, and/or re-triggering your bug. The most +frustrating thing for maintainers is for someone to report a bug, and then +never follow up on a request to try out a fix. + +That said, it's still useful for a kernel maintainer to know a bug exists +on a supported kernel, even if you can't follow up with retests. Follow +up reports, such as replying to the email thread with "I tried the latest +kernel and I can't reproduce my bug anymore" are also helpful, because +maintainers have to assume silence means things are still broken. + +Expectations for kernel maintainers +----------------------------------- + +Linux kernel maintainers are busy, overworked human beings. Some times +they may not be able to address your bug in a day, a week, or two weeks. +If they don't answer your email, they may be on vacation, or at a Linux +conference. Check the conference schedule at https://LWN.net for more info: + + https://lwn.net/Calendar/ + +In general, kernel maintainers take 1 to 5 business days to respond to +bugs. The majority of kernel maintainers are employed to work on the +kernel, and they may not work on the weekends. Maintainers are scattered +around the world, and they may not work in your time zone. Unless you +have a high priority bug, please wait at least a week after the first bug +report before sending the maintainer a reminder email. + +The exceptions to this rule are regressions, kernel crashes, security holes, +or userspace breakage caused by new kernel behavior. Those bugs should be +addressed by the maintainers ASAP. If you suspect a maintainer is not +responding to these types of bugs in a timely manner (especially during a +merge window), escalate the bug to LKML and Linus Torvalds. + +Thank you! + +[Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ] |