netdev FAQ¶
Q: What is netdev?¶
A: It is a mailing list for all network-related Linux stuff. Thisincludes anything found under net/ (i.e. core code like IPv6) anddrivers/net (i.e. hardware specific drivers) in the Linux source tree.
Note that some subsystems (e.g. wireless drivers) which have a highvolume of traffic have their own specific mailing lists.
The netdev list is managed (like many other Linux mailing lists) throughVGER (http://vger.kernel.org/) and archives can be found below:
Aside from subsystems like that mentioned above, all network-relatedLinux development (i.e. RFC, review, comments, etc.) takes place onnetdev.
Q: How do the changes posted to netdev make their way into Linux?¶
A: There are always two trees (git repositories) in play. Both aredriven by David Miller, the main network maintainer. There is thenet tree, and thenet-next tree. As you can probably guess fromthe names, thenet tree is for fixes to existing code already in themainline tree from Linus, andnet-next is where the new code goesfor the future release. You can find the trees here:
Q: How often do changes from these trees make it to the mainline Linus tree?¶
A: To understand this, you need to know a bit of background information onthe cadence of Linux development. Each new release starts off with atwo week “merge window” where the main maintainers feed their new stuffto Linus for merging into the mainline tree. After the two weeks, themerge window is closed, and it is called/tagged-rc1. No newfeatures get mainlined after this – only fixes to the rc1 content areexpected. After roughly a week of collecting fixes to the rc1 content,rc2 is released. This repeats on a roughly weekly basis until rc7(typically; sometimes rc6 if things are quiet, or rc8 if things are in astate of churn), and a week after the last vX.Y-rcN was done, theofficial vX.Y is released.
Relating that to netdev: At the beginning of the 2-week merge window,thenet-next tree will be closed - no new changes/features. Theaccumulated new content of the past ~10 weeks will be passed ontomainline/Linus via a pull request for vX.Y – at the same time, thenet tree will start accumulating fixes for this pulled contentrelating to vX.Y
An announcement indicating whennet-next has been closed is usuallysent to netdev, but knowing the above, you can predict that in advance.
IMPORTANT: Do not send newnet-next content to netdev during theperiod during whichnet-next tree is closed.
Shortly after the two weeks have passed (and vX.Y-rc1 is released), thetree fornet-next reopens to collect content for the next (vX.Y+1)release.
If you aren’t subscribed to netdev and/or are simply unsure ifnet-next has re-opened yet, simply check thenet-next gitrepository link above for any new networking-related commits. You mayalso check the following website for the current status:
Thenet tree continues to collect fixes for the vX.Y content, and isfed back to Linus at regular (~weekly) intervals. Meaning that thefocus fornet is on stabilization and bug fixes.
Finally, the vX.Y gets released, and the whole cycle starts over.
Q: So where are we now in this cycle?
Load the mainline (Linus) page here:
and note the top of the “tags” section. If it is rc1, it is early inthe dev cycle. If it was tagged rc7 a week ago, then a release isprobably imminent.
Q: How do I indicate which tree (net vs. net-next) my patch should be in?¶
A: Firstly, think whether you have a bug fix or new “next-like” content.Then once decided, assuming that you use git, use the prefix flag, i.e.
git format-patch --subject-prefix='PATCH net-next' start..finish
Usenet instead ofnet-next (always lower case) in the above forbug-fixnet content. If you don’t use git, then note the only magicin the above is just the subject text of the outgoing e-mail, and youcan manually change it yourself with whatever MUA you are comfortablewith.
Q: I sent a patch and I’m wondering what happened to it?¶
Q: How can I tell whether it got merged?A: Start by looking at the main patchworks queue for netdev:
The “State” field will tell you exactly where things are at with yourpatch.
Q: The above only says “Under Review”. How can I find out more?¶
A: Generally speaking, the patches get triaged quickly (in less than48h). So be patient. Asking the maintainer for status updates on yourpatch is a good way to ensure your patch is ignored or pushed to thebottom of the priority list.
Q: I submitted multiple versions of the patch series¶
Q: should I directly update patchwork for the previous versions of thesepatch series?A: No, please don’t interfere with the patch status on patchwork, leaveit to the maintainer to figure out what is the most recent and currentversion that should be applied. If there is any doubt, the maintainerwill reply and ask what should be done.
Q: I made changes to only a few patches in a patch series should I resend only those changed?¶
A: No, please resend the entire patch series and make sure you do number yourpatches such that it is clear this is the latest and greatest set of patchesthat can be applied.
Q: I submitted multiple versions of a patch series and it looks like a version other than the last one has been accepted, what should I do?¶
A: There is no revert possible, once it is pushed out, it stays like that.Please send incremental versions on top of what has been merged in order to fixthe patches the way they would look like if your latest patch series was to bemerged.
Q: How can I tell what patches are queued up for backporting to the various stable releases?¶
A: Normally Greg Kroah-Hartman collects stable commits himself, but fornetworking, Dave collects up patches he deems critical for thenetworking subsystem, and then hands them off to Greg.
There is a patchworks queue that you can see here:
It contains the patches which Dave has selected, but not yet handed offto Greg. If Greg already has the patch, then it will be here:
A quick way to find whether the patch is in this stable-queue is tosimply clone the repo, and then git grep the mainline commit ID, e.g.
stable-queue$ git grep -l 284041ef21fdf2ereleases/3.0.84/ipv6-fix-possible-crashes-in-ip6_cork_release.patchreleases/3.4.51/ipv6-fix-possible-crashes-in-ip6_cork_release.patchreleases/3.9.8/ipv6-fix-possible-crashes-in-ip6_cork_release.patchstable/stable-queue$
Q: I see a network patch and I think it should be backported to stable.¶
Q: Should I request it viastable@vger.kernel.org like the references inthe kernel’s Documentation/process/stable-kernel-rules.rst file say?A: No, not for networking. Check the stable queues as per above firstto see if it is already queued. If not, then send a mail to netdev,listing the upstream commit ID and why you think it should be a stablecandidate.
Before you jump to go do the above, do note that the normal stable rulesinDocumentation/process/stable-kernel-rules.rststill apply. So you need to explicitly indicate why it is a criticalfix and exactly what users are impacted. In addition, you need toconvince yourself that youreally think it has been overlooked,vs. having been considered and rejected.
Generally speaking, the longer it has had a chance to “soak” inmainline, the better the odds that it is an OK candidate for stable. Soscrambling to request a commit be added the day after it appears shouldbe avoided.
Q: I have created a network patch and I think it should be backported to stable.¶
Q: Should I add a Cc:stable@vger.kernel.org like the references in thekernel’s Documentation/ directory say?A: No. See above answer. In short, if you think it really belongs instable, then ensure you write a decent commit log that describes whogets impacted by the bug fix and how it manifests itself, and when thebug was introduced. If you do that properly, then the commit will gethandled appropriately and most likely get put in the patchworks stablequeue if it really warrants it.
If you think there is some valid information relating to it being instable that doesnot belong in the commit log, then use the three dashmarker line as described inDocumentation/process/submitting-patches.rstto temporarily embed that information into the patch that you send.
Q: Are all networking bug fixes backported to all stable releases?¶
A: Due to capacity, Dave could only take care of the backports for thelast two stable releases. For earlier stable releases, each stablebranch maintainer is supposed to take care of them. If you find anypatch is missing from an earlier stable branch, please notifystable@vger.kernel.org with either a commit ID or a formal patchbackported, and CC Dave and other relevant networking developers.
Q: Is the comment style convention different for the networking content?¶
A: Yes, in a largely trivial way. Instead of this:
/* * foobar blah blah blah * another line of text */
it is requested that you make it look like this:
/* foobar blah blah blah * another line of text */
Q: I am working in existing code that has the former comment style and not the latter.¶
Q: Should I submit new code in the former style or the latter?A: Make it the latter style, so that eventually all code in the domainof netdev is of this format.
Q: I found a bug that might have possible security implications or similar.¶
Q: Should I mail the main netdev maintainer off-list?**A: No. The current netdev maintainer has consistently requested thatpeople use the mailing lists and not reach out directly. If you aren’tOK with that, then perhaps consider mailingsecurity@kernel.org orreading abouthttp://oss-security.openwall.org/wiki/mailing-lists/distrosas possible alternative mechanisms.
Q: What level of testing is expected before I submit my change?¶
A: If your changes are againstnet-next, the expectation is that youhave tested by layering your changes on top ofnet-next. Ideallyyou will have done run-time testing specific to your change, but at aminimum, your changes should survive anallyesconfig and anallmodconfig build without new warnings or failures.
Q: Any other tips to help ensure my net/net-next patch gets OK’d?¶
A: Attention to detail. Re-read your own work as if you were thereviewer. You can start with usingcheckpatch.pl, perhaps even withthe--strict flag. But do not be mindlessly robotic in doing so.If your change is a bug fix, make sure your commit log indicates theend-user visible symptom, the underlying reason as to why it happens,and then if necessary, explain why the fix proposed is the best way toget things done. Don’t mangle whitespace, and as is common, don’tmis-indent function arguments that span multiple lines. If it is yourfirst patch, mail it to yourself so you can test apply it to anunpatched tree to confirm infrastructure didn’t mangle it.
Finally, go back and readDocumentation/process/submitting-patches.rstto be sure you are not repeating some common mistake documented there.