[14:02] <FurretUber> Hi, I found a memory leak on i915 on the kernel 5.0.0-7 and 5.0.0-8 from Disco Dingo. It seems similar to another i915 leak where it leaks when Vulkan applications are used
[14:03] <tjaalton> FurretUber: please file it upstream
[14:03] <tjaalton> so we'll get a fix via the stable branch, maybe
[14:05] <kubkde> hey there fellers. i'm interested in rebuilding my kernel to include f2fs modules. is this the correct channel or should i be using a support channel instead?
[14:20] <kubkde> i should be cloning the git repo from kernel.ubuntu.com, correct? I've seen others use apt to pull
[14:34] <kubkde> So do I really have to download the whole thing? 
[14:35] <kubkde> I didn't expect to download 800+ MB to add a couple modules lol
[16:31] <stgraber> https://bugs.launchpad.net/ubuntu/+source/linux-meta-lts-xenial/+bug/1820526 is a bit of a problem
[16:51] <arighi>  /q tru
[16:51] <klebers> apw, ^ our linux-meta-lts-xenial is producing a linux-signed-generic-lts-xenial that depends on linux-generic instead of linux-generic-lts-xenial
[19:03] <kubkde> How can I load f2fs modules into a kernel to compile?
[19:03] <chiluk> @apw @cking ... Here's my last few months of work rolled up into an e-mail.  https://lkml.org/lkml/2019/3/18/706
[19:04] <kubkde> And in a broader sense, is the page linked in the topic up to date? 
[19:04] <chiluk> afaik I've seen 512ac99 accepted on some of the linux-stable trees.  I'm not sure who's doing stable maintenance any more, but you might want to watch out on this one.
[19:05] <cking> chiluk, this is excellent analysis; thanks for the heads up on this
[19:05] <cking> ..be interesting to see what upstream says about it
[19:06] <chiluk> Yeah I figured you guys might want a heads up...
[19:06] <chiluk> especially with the stable submissions... and performance is hard kind of issues.
[19:07] <kubkde> is https://wiki.ubuntu.com/Kernel/ well rounded enough to learn from? 
[19:07] <chiluk> You can definitely learn from it.
[19:08] <chiluk> what are you trying to accomplish kubkde? 
[19:08] <chiluk> you might want to try with the Documentation directory in the linux kernel source...
[19:10] <kubkde> chiluk, thanks for replying. I want to rebuild a kernel to include f2fs so I don't have to use dracut or initramfs. And also see if what I could accomplish/make 'better' from compiling my own.
[19:11] <chiluk> You are unlikely to make much if anything "better" imho.. but you definitely can turn on the flag..
[19:11] <chiluk> and yes that documentation is the best place to go for compiling Ubuntu kernels with the Ubuntu specific patches 
[19:11] <chiluk> so you don't break anything.
[19:14] <kubkde> chiluk, I'll take a look at the documentation direction right now, thanks. Would I be applying the patches after I've done my modifications? Also, what do people generally modify kernels to do? I saw one called 'XanMod' and it looked...the same?
[19:15] <kubkde> Christ this is thick.
[19:15] <chiluk> People who generally modify kernels are the same who don't know what they are doing...
[19:16] <chiluk> in general the only time you should modify kernel sources is if you are fixing something that is broken, and directly fixing c code
[19:16] <chiluk> or you need to do something specific like enable a module that is not enabled.
[19:16] <kubkde> How long have you been developing? I don't mind the reading but I'm afraid I might end up forgetting to go to work.
[19:16] <kubkde> I see
[19:17] <chiluk> kubkde..  in your case.. .I just checked and CONFIG_F2FS_FS=m is already set in the 4.15 ubuntu kernels
[19:17] <chiluk> you may simply need to modprobe f2fs to get things functioning.
[19:18] <kubkde> :O
[19:18] <chiluk> really you are unlikely to see any performance differences from building a custom kernel..
[19:18] <chiluk> sometimes even turning on architecture specific optimizations for your specific cpu end up in regressing performance.
[19:18] <kubkde> How do you check that? And doing modprobe f2fs doesn't work. I'll try to pull up the specific errors I got in regards to f2fs 
[19:19] <chiluk> but I'd love to hear how that goes.
[19:19] <chiluk> kubkde ... you need to "sudo modprobe f2fs"
[19:19] <kubkde> chiluk, that's definitely what I figured. What I plan to do is strip it down to be hardware specific 
[19:19] <chiluk> that's the thing though.
[19:20] <kubkde> Of course...sudo modprobe f2fs. I chrooted into the install after it was done, too
[19:20] <chiluk> so much is built as modules now that nothing is loaded that doesn't need to be there.
[19:20] <kubkde> Interesting
[19:23] <chiluk> the other problem is that so much of the kernel is integer logic that the differences between architectures are almost negligible as all of the fancy architecture specific bits  *(aes, simd, sse, etc) don't really apply to the kernel.
[19:25] <chiluk> kubkde... good luck though.. I'd love to hear if you make something faster.. You definitely can make the memory footprint smaller.  but ram is cheap these days.
[19:27] <kubkde> chiluk, I've got so many questions but I don't want to be that pita looking to be spoonfed haha. Reducing memory would be huge for me since my VMs keep eating it all up. 
[19:28] <kubkde> Of the encyclopedia of that documentation folder, which one do you think would be best to start with? 
[19:28] <chiluk> you should look at the cloud kernels instead
[19:28] <kubkde> cloud kernels?
[19:28] <kubkde> woah wtf
[19:28] <chiluk> sorry apt install linux-image-virtual
[19:29] <chiluk> those are minimal kernels that only support cloud architectures ..
[19:29] <chiluk> i.e. xen, kvm, .. not sure if others are supported... maybe vbox..
[19:29] <chiluk> kubkde... did I make your day?
[19:30] <kubkde> chiluk, you sure did :p
[19:31] <chiluk> kubkde... as for learning kernel internals/adminning I'd start with Documentation/admin-guide... 
[19:31] <chiluk> if you only care about ubuntu kernels the wiki you linked is probably best.
[19:31] <chiluk> but it assumes you know a lot of the stuff in the Documentation folder.
[19:31] <kubkde> Thanks, I really appreciate all the info you've given me. I run most VMs locally but even the idea of cloud kernels. Still wtf'ing lol. 
[19:31] <kubkde> I see, that's somewhat ironic
[19:33] <chiluk> 'tsall good ... those are not well publicized.... glad to be of service..
[19:35] <chiluk> kubkde just to be explicit the virtual kernels are supposed to be run in the guests not the host.
[19:37] <kubkde> I'm going to stick with Ubuntu so I don't get sidetracked. Ideally once I get good, I'm going to check out cloud kernels since it'd be useful on a resume and for my own media servers lol. 
[19:37] <kubkde> Sure that makes sense, thanks for the clarification
[19:38] <kubkde> It feels like once someone knows how to write a kernel a whole other world of possibility is unlocked 
[19:38] <kubkde> understands a kernel* rather than how to write one
[19:42] <kubkde> Alright....I can't believe you actually read through this chiluk 
[19:43] <chiluk> kubkde: to be truthful, I only check this once every month or so, and usually it's just to harass my canonical friends about cool stuff I'm working on... so you got REALLY lucky.
[19:43] <kubkde> :o
[19:43] <kubkde> :O
[19:43] <kubkde> holy sh*t lol
[19:43] <chiluk> yeah..
[19:44] <kubkde> I didn't even recognize
[19:44] <kubkde> Lol
[19:44] <chiluk> usually this channel is kind of one of those things where you ask, and then wait a day and see if someone responds.
[19:44] <chiluk> usually someone does.
[19:44] <kubkde> Then I got really really lucky
[19:45] <kubkde> You've got my gratitude chiluk :)
[19:45] <chiluk> although if you are just learning ... start with the admin-guide... have fun building a custom kernel.. see if you find any performance improvements... *(I have a feeling you won't)... there's a lot to learn.
[19:46] <kubkde> What's the general timeframe I should be expecting to have a full understanding?
[19:50] <kubkde> And sorry to bug because I'm sure you're busy, but I couldn't find any documentation on a module named (I think) libcrc32c
[19:51] <chiluk> kubkde... never... Linus does not claim to have a full understanding.  As for your module, probably start with modinfo libcrc32c .. then you might have to go to the source.
[19:52] <chiluk> fortunately modules are usually a pretty good place to start learning kernel programming as they tend to be more self-contained than other parts of the code base...
[19:52] <chiluk> another thing to do is actually read a book... I can recommend "linux kernel development" by robert love
[19:53] <chiluk> but may expects that you already know a bunch of os fundamentals
[19:58] <kubkde> Ah that would be an issue
[19:58] <chiluk> cool I'm out kubkde... good luck.. I've done my good dead for the month.
[19:59] <kubkde> Turns out I just need to build and install crc32c to run dracut -f --add-drivers f2fs successfully
[19:59] <kubkde> And yeah for sure
[19:59] <kubkde> Thanks for all the tips! 
[19:59] <kubkde> Today's my lucky day lol
[20:00] <kubkde> Take care chiluk, see you in a month
[20:00] <wxl> hey folks. i seem to be having a problem building upstream virtualbox kernel modules in xenial/4.4.0-143 but the bug seems to be related to 4.4.169 and on. this is true in all of the version they have available from 5.0-6.0. and yet the ubuntu version (5.1) works fine. seems related to a api change https://bugzilla.kernel.org/show_bug.cgi?id=202365 but i'm confused as to how being on an older kernel 
[20:00] <wxl> i'm still having this problem. any insight?
[20:07] <chiluk> kubkde dract is a fedora initramfs builder.. you are probably going to want update-initramfs instead ..
[20:13] <kubkde> chiluk, right, but the f2fs module either still wasn't loading or something else wasn't working. I tried modprobe f2fs and added it in /etc/initramfs-tools/modules. I do know that all the crc* modules have to be loaded from reading Fedora/Arch forums. Grub's current git (2.03~) has f2fs but it fails make-check. Dracut actually worked once...but once. So the plan is to rebuild a kernel to have all those modules in 
[20:13] <kubkde> it...although after reading that kernels are mostly full of modules I don't know if compiling my own would be a solution to having f2fs as my root partition
[20:54] <kubkde> btw chiluk if you're still around is there anything you think is exciting that's coming up in the new kernels or that could be added? And I know Dracut is for Fedora, but does that mean I'm more than likely to just break more things when I could be using initramfs-tools lol
[21:11] <chiluk> ^^ it could break things you are unaware of.
[22:58] <FurretUber> Earlier today I found a memory leak on i915 on kernel 5.0. It was asked to report on upstream. I did the bisect but where should I report it? 
[22:59] <FurretUber> As this is fixed on 5.1-rc1, for FreeDesktop bugzilla it would be considered already fixed
[23:51] <tomreyn> FurretUber: https://www.kernel.org/ states that 5.0(.2) is a stable branch, and the latest. i think FDO would still care having it fixed in the 5.0 branch.