Commit | Line | Data |
---|---|---|
2c97a63f SS |
1 | Background |
2 | ========== | |
3 | ||
4 | The upstream Linux kernel maintainers only fix bugs for specific kernel | |
5 | versions. Those versions include the current "release candidate" (or -rc) | |
6 | kernel, any "stable" kernel versions, and any "long term" kernels. | |
7 | ||
8 | Please see https://www.kernel.org/ for a list of supported kernels. Any | |
9 | kernel marked with [EOL] is "end of life" and will not have any fixes | |
10 | backported to it. | |
11 | ||
12 | If you've found a bug on a kernel version 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 | ||
18 | ||
19 | How to report Linux kernel bugs | |
20 | =============================== | |
21 | ||
22 | ||
d60418bc SS |
23 | Identify the problematic subsystem |
24 | ---------------------------------- | |
25 | ||
26 | Identifying which part of the Linux kernel might be causing your issue | |
27 | increases your chances of getting your bug fixed. Simply posting to the | |
28 | generic linux-kernel mailing list (LKML) may cause your bug report to be | |
29 | lost in the noise of a mailing list that gets 1000+ emails a day. | |
30 | ||
31 | Instead, try to figure out which kernel subsystem is causing the issue, | |
32 | and email that subsystem's maintainer and mailing list. If the subsystem | |
33 | maintainer doesn't answer, then expand your scope to mailing lists like | |
34 | LKML. | |
35 | ||
36 | ||
37 | Identify who to notify | |
38 | ---------------------- | |
39 | ||
40 | Once you know the subsystem that is causing the issue, you should send a | |
41 | bug report. Some maintainers prefer bugs to be reported via bugzilla | |
42 | (https://bugzilla.kernel.org), while others prefer that bugs be reported | |
43 | via the subsystem mailing list. | |
44 | ||
45 | To find out where to send an emailed bug report, find your subsystem or | |
46 | device driver in the MAINTAINERS file. Search in the file for relevant | |
47 | entries, and send your bug report to the person(s) listed in the "M:" | |
48 | lines, making sure to Cc the mailing list(s) in the "L:" lines. When the | |
49 | maintainer replies to you, make sure to 'Reply-all' in order to keep the | |
50 | public mailing list(s) in the email thread. | |
51 | ||
52 | If you know which driver is causing issues, you can pass one of the driver | |
53 | files to the get_maintainer.pl script: | |
54 | perl scripts/get_maintainer.pl -f <filename> | |
55 | ||
56 | If it is a security bug, please copy the Security Contact listed in the | |
57 | MAINTAINERS file. They can help coordinate bugfix and disclosure. See | |
58 | Documentation/SecurityBugs for more information. | |
59 | ||
60 | If you can't figure out which subsystem caused the issue, you should file | |
61 | a bug in kernel.org bugzilla and send email to | |
62 | linux-kernel@vger.kernel.org, referencing the bugzilla URL. (For more | |
63 | information on the linux-kernel mailing list see | |
64 | http://www.tux.org/lkml/). | |
65 | ||
66 | ||
bf6adaf5 SS |
67 | Tips for reporting bugs |
68 | ----------------------- | |
69 | ||
70 | If you haven't reported a bug before, please read: | |
71 | ||
72 | http://www.chiark.greenend.org.uk/~sgtatham/bugs.html | |
73 | http://www.catb.org/esr/faqs/smart-questions.html | |
74 | ||
75 | It's REALLY important to report bugs that seem unrelated as separate email | |
76 | threads or separate bugzilla entries. If you report several unrelated | |
77 | bugs at once, it's difficult for maintainers to tease apart the relevant | |
78 | data. | |
79 | ||
1da177e4 | 80 | |
7883a250 SS |
81 | Gather information |
82 | ------------------ | |
3b12c21a | 83 | |
7883a250 SS |
84 | The most important information in a bug report is how to reproduce the |
85 | bug. This includes system information, and (most importantly) | |
86 | step-by-step instructions for how a user can trigger the bug. | |
3b12c21a | 87 | |
7883a250 SS |
88 | If the failure includes an "OOPS:", take a picture of the screen, capture |
89 | a netconsole trace, or type the message from your screen into the bug | |
90 | report. Please read "Documentation/oops-tracing.txt" before posting your | |
91 | bug report. This explains what you should do with the "Oops" information | |
92 | to make it useful to the recipient. | |
1da177e4 | 93 | |
7883a250 SS |
94 | This is a suggested format for a bug report sent via email or bugzilla. |
95 | Having a standardized bug report form makes it easier for you not to | |
9dcbb32f | 96 | overlook things, and easier for the developers to find the pieces of |
7883a250 SS |
97 | information they're really interested in. If some information is not |
98 | relevant to your bug, feel free to exclude it. | |
1da177e4 | 99 | |
3b12c21a | 100 | First run the ver_linux script included as scripts/ver_linux, which |
1da177e4 LT |
101 | reports the version of some important subsystems. Run this script with |
102 | the command "sh scripts/ver_linux". | |
103 | ||
104 | Use that information to fill in all fields of the bug report form, and | |
105 | post it to the mailing list with a subject of "PROBLEM: <one line | |
9dcbb32f | 106 | summary from [1.]>" for easy identification by the developers. |
1da177e4 | 107 | |
9dcbb32f | 108 | [1.] One line summary of the problem: |
1da177e4 LT |
109 | [2.] Full description of the problem/report: |
110 | [3.] Keywords (i.e., modules, networking, kernel): | |
4e229bef RD |
111 | [4.] Kernel information |
112 | [4.1.] Kernel version (from /proc/version): | |
113 | [4.2.] Kernel .config file: | |
30e835e3 AM |
114 | [5.] Most recent kernel version which did not have the bug: |
115 | [6.] Output of Oops.. message (if applicable) with symbolic information | |
1da177e4 | 116 | resolved (see Documentation/oops-tracing.txt) |
30e835e3 | 117 | [7.] A small shell script or example program which triggers the |
1da177e4 | 118 | problem (if possible) |
30e835e3 AM |
119 | [8.] Environment |
120 | [8.1.] Software (add the output of the ver_linux script here) | |
121 | [8.2.] Processor information (from /proc/cpuinfo): | |
122 | [8.3.] Module information (from /proc/modules): | |
123 | [8.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem) | |
124 | [8.5.] PCI information ('lspci -vvv' as root) | |
125 | [8.6.] SCSI information (from /proc/scsi/scsi) | |
126 | [8.7.] Other information that might be relevant to the problem | |
1da177e4 LT |
127 | (please look in /proc and include all information that you |
128 | think to be relevant): | |
129 | [X.] Other notes, patches, fixes, workarounds: | |
130 | ||
131 | ||
bc6bed48 SS |
132 | Follow up |
133 | ========= | |
134 | ||
135 | Expectations for bug reporters | |
136 | ------------------------------ | |
137 | ||
138 | Linux kernel maintainers expect bug reporters to be able to follow up on | |
139 | bug reports. That may include running new tests, applying patches, | |
140 | recompiling your kernel, and/or re-triggering your bug. The most | |
141 | frustrating thing for maintainers is for someone to report a bug, and then | |
142 | never follow up on a request to try out a fix. | |
143 | ||
144 | That said, it's still useful for a kernel maintainer to know a bug exists | |
145 | on a supported kernel, even if you can't follow up with retests. Follow | |
146 | up reports, such as replying to the email thread with "I tried the latest | |
147 | kernel and I can't reproduce my bug anymore" are also helpful, because | |
148 | maintainers have to assume silence means things are still broken. | |
149 | ||
150 | Expectations for kernel maintainers | |
151 | ----------------------------------- | |
152 | ||
153 | Linux kernel maintainers are busy, overworked human beings. Some times | |
154 | they may not be able to address your bug in a day, a week, or two weeks. | |
155 | If they don't answer your email, they may be on vacation, or at a Linux | |
156 | conference. Check the conference schedule at LWN.net for more info: | |
157 | https://lwn.net/Calendar/ | |
158 | ||
159 | In general, kernel maintainers take 1 to 5 business days to respond to | |
160 | bugs. The majority of kernel maintainers are employed to work on the | |
161 | kernel, and they may not work on the weekends. Maintainers are scattered | |
162 | around the world, and they may not work in your time zone. Unless you | |
163 | have a high priority bug, please wait at least a week after the first bug | |
164 | report before sending the maintainer a reminder email. | |
165 | ||
166 | The exceptions to this rule are regressions, kernel crashes, security holes, | |
167 | or userspace breakage caused by new kernel behavior. Those bugs should be | |
168 | addressed by the maintainers ASAP. If you suspect a maintainer is not | |
169 | responding to these types of bugs in a timely manner (especially during a | |
170 | merge window), escalate the bug to LKML and Linus Torvalds. | |
171 | ||
172 | Thank you! | |
b7ca36ae SS |
173 | |
174 | [Some of this is taken from Frohwalt Egerer's original linux-kernel FAQ] |