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diff --git a/Documentation/admin-guide/reporting-issues.rst b/Documentation/admin-guide/reporting-issues.rst index 2fd5a030235a..16a66a1f1975 100644 --- a/Documentation/admin-guide/reporting-issues.rst +++ b/Documentation/admin-guide/reporting-issues.rst @@ -41,13 +41,23 @@ If you are facing multiple issues with the Linux kernel at once, report each separately. While writing your report, include all information relevant to the issue, like the kernel and the distro used. In case of a regression, CC the regressions mailing list (regressions@lists.linux.dev) to your report. Also try -to pin-point the culprit with a bisection; if you succeed, include its +to pinpoint the culprit with a bisection; if you succeed, include its commit-id and CC everyone in the sign-off-by chain. Once the report is out, answer any questions that come up and help where you can. That includes keeping the ball rolling by occasionally retesting with newer releases and sending a status update afterwards. +.. + Note: If you see this note, you are reading the text's source file. You + might want to switch to a rendered version: It makes it a lot easier to + read and navigate this document -- especially when you want to look something + up in the reference section, then jump back to where you left off. +.. + Find the latest rendered version of this text here: + https://docs.kernel.org/admin-guide/reporting-issues.html + + Step-by-step guide how to report issues to the kernel maintainers ================================================================= @@ -206,7 +216,7 @@ Reporting issues only occurring in older kernel version lines This subsection is for you, if you tried the latest mainline kernel as outlined above, but failed to reproduce your issue there; at the same time you want to see the issue fixed in a still supported stable or longterm series or vendor -kernels regularly rebased on those. If that the case, follow these steps: +kernels regularly rebased on those. If that is the case, follow these steps: * Prepare yourself for the possibility that going through the next few steps might not get the issue solved in older releases: the fix might be too big @@ -231,45 +241,54 @@ kernels regularly rebased on those. If that the case, follow these steps: The reference section below explains each of these steps in more detail. +Conclusion of the step-by-step guide +------------------------------------ + +Did you run into trouble following the step-by-step guide not cleared up by the +reference section below? Did you spot errors? Or do you have ideas on how to +improve the guide? + +If any of that applies, please let the developers know by sending a short note +or a patch to Thorsten Leemhuis <linux@leemhuis.info> while ideally CCing the +public Linux docs mailing list <linux-doc@vger.kernel.org>. Such feedback is +vital to improve this text further, which is in everybody's interest, as it will +enable more people to master the task described here. + + Reference section: Reporting issues to the kernel maintainers ============================================================= -The detailed guides above outline all the major steps in brief fashion, which -should be enough for most people. But sometimes there are situations where even -experienced users might wonder how to actually do one of those steps. That's -what this section is for, as it will provide a lot more details on each of the -above steps. Consider this as reference documentation: it's possible to read it -from top to bottom. But it's mainly meant to skim over and a place to look up -details how to actually perform those steps. - -A few words of general advice before digging into the details: - - * The Linux kernel developers are well aware this process is complicated and - demands more than other FLOSS projects. We'd love to make it simpler. But - that would require work in various places as well as some infrastructure, - which would need constant maintenance; nobody has stepped up to do that - work, so that's just how things are for now. - - * A warranty or support contract with some vendor doesn't entitle you to - request fixes from developers in the upstream Linux kernel community: such - contracts are completely outside the scope of the Linux kernel, its - development community, and this document. That's why you can't demand - anything such a contract guarantees in this context, not even if the - developer handling the issue works for the vendor in question. If you want - to claim your rights, use the vendor's support channel instead. When doing - so, you might want to mention you'd like to see the issue fixed in the - upstream Linux kernel; motivate them by saying it's the only way to ensure - the fix in the end will get incorporated in all Linux distributions. - - * If you never reported an issue to a FLOSS project before you should consider - reading `How to Report Bugs Effectively - <https://www.chiark.greenend.org.uk/~sgtatham/bugs.html>`_, `How To Ask - Questions The Smart Way - <http://www.catb.org/esr/faqs/smart-questions.html>`_, and `How to ask good - questions <https://jvns.ca/blog/good-questions/>`_. - -With that off the table, find below the details on how to properly report -issues to the Linux kernel developers. +The step-by-step guide above outlines all the major steps in brief fashion, +which usually covers everything required. But even experienced users will +sometimes wonder how to actually realize some of those steps or why they are +needed; there are also corner cases the guide ignores for readability. That is +what the entries in this reference section are for, which provide additional +information for each of the steps in the guide. + +A few words of general advice: + +* The Linux developers are well aware that reporting bugs to them is more + complicated and demanding than in other FLOSS projects. Some of it is because + the kernel is different, among others due to its mail-driven development + process and because it consists mostly of drivers. Some of it is because + improving things would require work in several technical areas and people + triaging bugs –– and nobody has stepped up to do or fund that work. + +* A warranty or support contract with some vendor doesn't entitle you to + request fixes from the upstream Linux developers: Such contracts are + completely outside the scope of the upstream Linux kernel, its development + community, and this document -- even if those handling the issue work for the + vendor who issued the contract. If you want to claim your rights, use the + vendor's support channel. + +* If you never reported an issue to a FLOSS project before, consider skimming + guides like `How to ask good questions + <https://jvns.ca/blog/good-questions/>`_, `How To Ask Questions The Smart Way + <http://www.catb.org/esr/faqs/smart-questions.html>`_, and `How to Report + Bugs Effectively <https://www.chiark.greenend.org.uk/~sgtatham/bugs.html>`_,. + +With that off the table, find below details for the steps from the detailed +guide on reporting issues to the Linux kernel developers. Make sure you're using the upstream Linux kernel @@ -312,7 +331,7 @@ small modifications to a kernel based on a recent Linux version; that for example often holds true for the mainline kernels shipped by Debian GNU/Linux Sid or Fedora Rawhide. Some developers will also accept reports about issues with kernels from distributions shipping the latest stable kernel, as long as -its only slightly modified; that for example is often the case for Arch Linux, +it's only slightly modified; that for example is often the case for Arch Linux, regular Fedora releases, and openSUSE Tumbleweed. But keep in mind, you better want to use a mainline Linux and avoid using a stable kernel for this process, as outlined in the section 'Install a fresh kernel for testing' in more @@ -611,7 +630,7 @@ better place. How to read the MAINTAINERS file ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -To illustrate how to use the :ref:`MAINTAINERS <maintainers>` file, lets assume +To illustrate how to use the :ref:`MAINTAINERS <maintainers>` file, let's assume the WiFi in your Laptop suddenly misbehaves after updating the kernel. In that case it's likely an issue in the WiFi driver. Obviously it could also be some code it builds upon, but unless you suspect something like that stick to the @@ -1543,7 +1562,7 @@ as well, because that will speed things up. And note, it helps developers a great deal if you can specify the exact version that introduced the problem. Hence if possible within a reasonable time frame, -try to find that version using vanilla kernels. Lets assume something broke when +try to find that version using vanilla kernels. Let's assume something broke when your distributor released a update from Linux kernel 5.10.5 to 5.10.8. Then as instructed above go and check the latest kernel from that version line, say 5.10.9. If it shows the problem, try a vanilla 5.10.5 to ensure that no patches @@ -1674,72 +1693,59 @@ for the subsystem where the issue seems to have its roots; CC the mailing list for the subsystem as well as the stable mailing list (stable@vger.kernel.org). -Why some issues won't get any reaction or remain unfixed after being reported -============================================================================= - -When reporting a problem to the Linux developers, be aware only 'issues of high -priority' (regressions, security issues, severe problems) are definitely going -to get resolved. The maintainers or if all else fails Linus Torvalds himself -will make sure of that. They and the other kernel developers will fix a lot of -other issues as well. But be aware that sometimes they can't or won't help; and -sometimes there isn't even anyone to send a report to. - -This is best explained with kernel developers that contribute to the Linux -kernel in their spare time. Quite a few of the drivers in the kernel were -written by such programmers, often because they simply wanted to make their -hardware usable on their favorite operating system. - -These programmers most of the time will happily fix problems other people -report. But nobody can force them to do, as they are contributing voluntarily. - -Then there are situations where such developers really want to fix an issue, -but can't: sometimes they lack hardware programming documentation to do so. -This often happens when the publicly available docs are superficial or the -driver was written with the help of reverse engineering. - -Sooner or later spare time developers will also stop caring for the driver. -Maybe their test hardware broke, got replaced by something more fancy, or is so -old that it's something you don't find much outside of computer museums -anymore. Sometimes developer stops caring for their code and Linux at all, as -something different in their life became way more important. In some cases -nobody is willing to take over the job as maintainer – and nobody can be forced -to, as contributing to the Linux kernel is done on a voluntary basis. Abandoned -drivers nevertheless remain in the kernel: they are still useful for people and -removing would be a regression. - -The situation is not that different with developers that are paid for their -work on the Linux kernel. Those contribute most changes these days. But their -employers sooner or later also stop caring for their code or make its -programmer focus on other things. Hardware vendors for example earn their money -mainly by selling new hardware; quite a few of them hence are not investing -much time and energy in maintaining a Linux kernel driver for something they -stopped selling years ago. Enterprise Linux distributors often care for a -longer time period, but in new versions often leave support for old and rare -hardware aside to limit the scope. Often spare time contributors take over once -a company orphans some code, but as mentioned above: sooner or later they will -leave the code behind, too. - -Priorities are another reason why some issues are not fixed, as maintainers -quite often are forced to set those, as time to work on Linux is limited. -That's true for spare time or the time employers grant their developers to -spend on maintenance work on the upstream kernel. Sometimes maintainers also -get overwhelmed with reports, even if a driver is working nearly perfectly. To -not get completely stuck, the programmer thus might have no other choice than -to prioritize issue reports and reject some of them. - -But don't worry too much about all of this, a lot of drivers have active -maintainers who are quite interested in fixing as many issues as possible. - - -Closing words -============= - -Compared with other Free/Libre & Open Source Software it's hard to report -issues to the Linux kernel developers: the length and complexity of this -document and the implications between the lines illustrate that. But that's how -it is for now. The main author of this text hopes documenting the state of the -art will lay some groundwork to improve the situation over time. - +Appendix: Why it is somewhat hard to report kernel bugs +======================================================= + +The Linux kernel developers are well aware that reporting bugs to them is harder +than in other Free/Libre Open Source Projects. Many reasons for that lie in the +nature of kernels, Linux' development model, and how the world uses the kernel: + +* *Most kernels of Linux distributions are totally unsuitable for reporting bugs + upstream.* The reference section above already explained this in detail: + outdated codebases as well as modifications and add-ons lead to kernel bugs + that were fixed upstream a long time ago or never happened there in the first + place. Developers of other Open Source software face these problems as well, + but the situation is a lot worse when it comes to the kernel, as the changes + and their impact are much more severe -- which is why many kernel developers + expect reports with kernels built from fresh and nearly unmodified sources. + +* *Bugs often only occur in a special environment.* That is because Linux is + mostly drivers and can be used in a multitude of ways. Developers often do not + have a matching setup at hand -- and therefore frequently must rely on bug + reporters for isolating a problems's cause and testing proposed fixes. + +* *The kernel has hundreds of maintainers, but all-rounders are very rare.* That + again is and effect caused by the multitude of features and drivers, due to + which many kernel developers know little about lower or higher layers related + to their code and even less about other areas. + +* *It is hard finding where to report issues to, among others, due to the lack + of a central bug tracker.* This is something even some kernel developers + dislike, but that's the situation everyone has to deal with currently. + +* *Stable and longterm kernels are primarily maintained by a dedicated 'stable + team', which only handles regressions introduced within stable and longterm + series.* When someone reports a bug, say, using Linux 6.1.2, the team will, + therefore, always ask if mainline is affected: if the bug already happened + in 6.1 or occurs with latest mainline (say, 6.2-rc3), they in everybody's + interest shove it to the regular developers, as those know the code best. + +* *Linux developers are free to focus on latest mainline.* Some, thus, react + coldly to reports about bugs in, say, Linux 6.0 when 6.1 is already out; + even the latter might not be enough once 6.2-rc1 is out. Some will also not + be very welcoming to reports with 6.1.5 or 6.1.6, as the problem might be a + series-specific regression the stable team (see above) caused and must fix. + +* *Sometimes there is nobody to help.* Sometimes this is due to the lack of + hardware documentation -- for example, when a driver was built using reverse + engineering or was taken over by spare-time developers when the hardware + manufacturer left it behind. Other times there is nobody to even report bugs + to: when maintainers move on without a replacement, their code often remains + in the kernel as long as it's useful. + +Some of these aspects could be improved to facilitate bug reporting -- many +Linux kernel developers are well aware of this and would be glad if a few +individuals or an entity would make this their mission. .. end-of-content |