/srv/irclogs.ubuntu.com/2017/04/24/#ubuntu-kernel.txt

chatter29hey guys02:16
chatter29allah is doing02:16
chatter29sun is not doing allah is doing02:16
chatter29to accept Islam say that i bear witness that there is no deity worthy of worship except Allah and Muhammad peace be upon him is his slave and messenger02:16
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tischHi, all. I'm new to reporting kernel bugs, but could I try my luck here?13:36
apwtisch, you are not in the wrong place13:55
tischthats good to know, i just wanted to gather some general information for submitting a bug regarding a mainline kernel (4.10.12)14:23
tischi've previously sumbitted to systemd, but the maintainer pointed me to the ubuntu kernel maintainers. See my report here: https://github.com/systemd/systemd/issues/5790#event-105466350314:25
apwgenerally they are keen for you to talk to whoever packaged what you are using14:27
apwas we might have broke it.  in the case of mainline kernel-ppa builds they are in theory14:27
apwraw upstream bits, so the testing is more relevant there14:27
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tischok, thanks apw. could you point me to a website where i would best submit this bug?14:29
apwwhat sort of bug is it ?14:32
tischusing the 4.10.12 kernel i'm unable to login on a gnome 16.04 system. The system freezes after putting in the login information. Same happens when I try to login from the shell14:37
tischThe following ouptut appears on the shell repeatedly:14:41
tischMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [systemd-logind:913y]14:41
apwtisch, sounds like a real bug indeed15:05
tischon 4.10.11 the issue does not appear. I also have the same issue on 4.11.0-rc815:11
apwsounds very bisectable then15:12
tischapw, i've never done a git bisect before. how can i aid the kernel team further to fix this bug. do you need hardware information?15:13
LocutusOfBorgtisch, can you reproduce with a different pc?15:40
tischLocutusOfBorg,yes, i could try to boot my old laptop and install the kernel version. it'll take a little momemt15:41
LocutusOfBorgdoes this happen with a vanilla kernel?15:42
LocutusOfBorgwhere did you get that kernel?15:42
tischi installed the kernel using the ukuu kernel updated gui tool on gnome 16.0415:43
tischso, it should be vanilla i guess15:44
LocutusOfBorgdoes this happen with 4.11.0-rc7?15:47
tischi just tried 4.10.11 (OK), 4.10.12 (error) and 4.11.0-rc8 (error) so far, but i can go ahead and try with 4.11.0-rc7 if it helps15:48
LocutusOfBorgyes15:48
tischok, one sec. i'll be back in a minute15:49
tischsame error on 4.11.0-rc715:54
LocutusOfBorgtisch, also, please test this packages http://kernel.ubuntu.com/~kernel-ppa/mainline/15:54
LocutusOfBorgoh, interesting15:54
LocutusOfBorgso it is needed to understand if rc5, rc6 works15:54
LocutusOfBorgto bisect we need to know the first rc broken15:55
tischok, i'll work my way down the kernel rcs for 4.11 then15:55
LocutusOfBorgyes, and also understanding if the kernel.ubuntu.com version works would be nice15:55
LocutusOfBorgmaybe this is a known and already patched/fixed issue15:55
LocutusOfBorgif the problem is on the rc kernel, it has been backported on the stable branch15:56
LocutusOfBorgand this is bad15:56
tischok,  understand, how do i install the kernel from the kernel ppa mainline website you sent? So far I've really just used a gui tool like ukuu15:57
LocutusOfBorgdownload the deb files from the website15:58
LocutusOfBorgand sudo dpkg -i *.deb15:58
LocutusOfBorgdownload only for your arch :)15:58
tischthe ones for 4.11.0-rc8, i guess then  (http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.11-rc8/)15:59
LocutusOfBorgexactly15:59
LocutusOfBorgor just dpkg -i various versions, so you can reboot a few times and quickly find the one that is bad15:59
LocutusOfBorg(if canonical version suffers from the same issue)15:59
tischjust out of my curiosity, those are not the same kernels which i already installed through ukuu?16:00
LocutusOfBorgthey carry some Ubuntu patch16:00
tischok, i see16:00
LocutusOfBorgwith a big value of "some"16:00
LocutusOfBorg:)16:00
tischok, so i downloaded the files for amd64 headers and generic without the lowlatency ones. i guess this is correct. 16:03
LocutusOfBorgtwo generic and one _all.deb you need16:05
LocutusOfBorgheaders-generic image-generic and _all.deb16:06
tischyeah, looks right16:06
tischand now sudo dpkg -i *.deb 16:06
LocutusOfBorgexactly16:06
* LocutusOfBorg will leave shortly16:07
tischok, it's installed. i'll reboot and be back in a minute16:07
tischsame issue with the downloaded kernel16:10
LocutusOfBorgwonderful16:10
LocutusOfBorgso this is an upstream issue not fixed by canonical16:10
LocutusOfBorgI would complain with upstream kernel devs in this case16:11
tischshould i report somewhere else?16:11
LocutusOfBorgbut bisecting and understanding when it has been introduced (at least the first bad rc) is required16:11
LocutusOfBorgso, please try to understand that16:11
LocutusOfBorgin case we find the commit, we can just email the author16:12
tischok, so i'll just work my way down the rcs16:12
LocutusOfBorgor send to kernel mail list16:12
LocutusOfBorgyep16:12
LocutusOfBorgyou can use the ppa versions, easier to install/remove16:12
tischcan i use the ukuu tool or d i have to download from the ubuntu kernel ppa website?16:12
tischwho should i talk to when i found the rc which introduced the regression?16:13
LocutusOfBorgto me it is fine16:13
LocutusOfBorgI will try to have a quick look16:13
tischthanks16:13
* LocutusOfBorg is going to take the train, will disconnect and reconnect16:13
tischok, so i'll work my way down. i'll write when i found the highest working rc version16:14
tischi just checked the ukuu documentation which repository the tool uses, the doc says: "Fetches list of kernels from kernel.ubuntu.com", so i guess those are the same as i manually downloaded and installed then16:30
tischLocutusOfBorg: kernel 4.11.0-rc6 works fine16:35
tischso the regression is introduced in rc7 i guess16:35
LocutusOfBorgarchitecture is amd64?16:43
LocutusOfBorgcpu is intel I would guess16:44
tischyes16:44
tischyes it's an i7-770016:44
LocutusOfBorginteresting16:44
LocutusOfBorgdoes this happen with other amd64 laptops?16:44
tischi haven't tried yet. but the other laptop i have at hand is pretty old. i guess it's first generation mobile i716:45
tischbuild date 200916:46
tischit's also an amd64 architecture though16:48
LocutusOfBorgnot sure, I see two commits that have been backported and are related to cpu16:50
LocutusOfBorgthis commit is really suspicious https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7f00f388712b29005782bad7e4b25942620f3b9c16:52
apwLocutusOfBorg, ugg, thanks16:52
LocutusOfBorgapw, do you agree? I would like to do a test-build for him without that commit16:53
LocutusOfBorgbut I never looked at the ubuntu kernel16:53
apwwhy is it suspicious ?16:54
apwit sounds like it fixes something legitimate16:54
LocutusOfBorgbecause git diff reveals only two changes in the cpu code16:55
LocutusOfBorgand the second one is not so interesting16:55
LocutusOfBorgthis one is about locks and race conditions16:55
LocutusOfBorgand both changes have been backported to stable, between 4.10.11-4.10.1216:55
LocutusOfBorghttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f2200ac311302fcdca6556fd0c5127eab6c65a3e16:55
LocutusOfBorgthis is the other one16:55
* LocutusOfBorg did grep for cpu16:56
apwwell cirtianly you could try reverting it, but we can likely spin you a test kernel if there is a bu16:56
apwbug associated with the issue16:56
LocutusOfBorgtisch, can you please open a bug and subscribe me?16:58
LocutusOfBorgI'm downloading the artful kernel, patch it, and upload into xenial ppa16:58
LocutusOfBorgand see if the stable+ the two commits is broken or not16:58
tischyes, sure. can you point me to a webpage where to open the bug16:58
LocutusOfBorgubuntu-bug linux should work17:00
LocutusOfBorgeven if opening bugs for not yet packaged linux versions is... strange17:00
apwit may not let you file a bug, with a non-official kernle installed, it is kinda picky17:01
LocutusOfBorgif my connection allows, I'm uploading a  4.10.0-19.21~ppa1 to my ppa17:02
LocutusOfBorgwith the two commits above17:02
LocutusOfBorgotherwise, git bisect ftw17:02
jsalisburyLocutusOfBorg, I can build some test kernels for you, if you need.17:15
LocutusOfBorgjsalisbury, http://paste.debian.net/929141/17:17
LocutusOfBorgthis patch on top of the latest kernel code you have (zesty?artful?)17:17
LocutusOfBorgif my assumption is correct, that will introduce the issue17:17
LocutusOfBorgbuild for xenial please17:17
jsalisburyLocutusOfBorg, that commit is upstream as of 4.11-rc7.  It's not in artful.  You want me to build you a Xenial test kernel with a pick of that commit?17:19
LocutusOfBorgjsalisbury, the artful kernel, with that upstream cherry-pick for xenial17:19
LocutusOfBorgI'm trying to bisect a regression between 4.11-rc6 and 4.11-rc7, and I would like to cherry-pick the two interesting commits, to see if an older kernel crashes with them17:20
jsalisburyLocutusOfBorg, will do.  did you happen to open a bug yet?  17:20
LocutusOfBorgno17:20
LocutusOfBorgit is a mainline issue right now :)17:20
LocutusOfBorgin case we reproduce the problem, either the first or the second commit will be the culprit, in that case I'll ask tisch to send emails to who wrote the patch and mail llists17:21
jsalisburyLocutusOfBorg, it would be helpful if you could open a bug, that way we can keep track of everything.  I should have a test kernel ready in about 20 minutes or so17:21
LocutusOfBorgI already asked tisch to do it, I'm not the person with that issue :)17:21
* LocutusOfBorg is leaving shortly17:21
tischyes, i can open the bug report17:22
jsalisburyLocutusOfBorg, ok.  17:22
jsalisburytisch, thanks17:22
tischno, guys, thanks goes to you for all the heavy lifting17:22
tischthe bug report should go here? https://bugs.launchpad.net/ubuntu/+source/linux17:23
LocutusOfBorgyep17:24
tischany suggestiosn for the summary and further information fields for the bug report?17:26
jsalisburytisch, just a basic description of the bug.17:27
tischok, will do17:27
tischhttps://bugs.launchpad.net/ubuntu/+source/linux/+bug/168586517:34
ubot5Ubuntu bug 1685865 in linux (Ubuntu) "Can't login after boot with Kernel 4.11.0-rc7, soft lockup in systemd-logind" [Undecided,New]17:34
tischthats the bug report, i've subscribed LocutusOfBorg and jsalisbury 17:34
jsalisburytisch, great, thanks17:35
LocutusOfBorgyep thanks17:35
jsalisburytisch, I have a test kernel building now.  I'll let you know when it's done.17:35
tischthanks joseph17:36
jsalisburynp17:36
tischi'll try to reproduce the bug on my other eold laptop (first gen mobile i7)17:36
jsalisburytisch, The test kernel is available for downloaded from:18:32
jsalisburyhttp://kernel.ubuntu.com/~jsalisbury/lp1685865/18:32
tischthanks, i'll install it right away. do i need to download and install all deb packages? 18:49
tischjsalisbury: or can i leave something like cloud-tools out?18:50
jsalisburytisch, just the linux-image and linux-image-extra .deb packages.18:50
tischjsalisbury: the issue seems to be fixed with the compiled test kernel18:59
ivanhttp://www.openwall.com/lists/oss-security/2017/04/24/419:00
jsalisburytisch, hmm, I think LocutusOfBorg believed this bug would happen if commit f2200ac311302f was added.19:01
jsalisburytisch, that might mean that commit is not the cause of the bug.19:01
tischok, thats unfortunate19:02
jsalisburytisch, I can perform a bisect to try an narrow down the offending commit19:02
jsalisburytisch, Just to confirm the bug happens with -rc7 but not -rc6?19:02
jsalisburytisch, also, have you tried -rc8 to see if the bug was already fixed?19:03
tischjsalisbury: sure, just to confirm, the kernel i booted right now is: uname -a19:03
tischLinux tisch-XPS-15-9560 4.10.0-19-generic #21~TestKernelWithCommitf2200ac3113 SMP Mon Apr 24 17:28:58 UTC  x86_64 x86_64 x86_64 GNU/Linux19:03
jsalisburytisch, yes, that looks correct19:03
tischjsalisbury: yes, the bug is present in all version higher than rc6 and 4.10.1219:03
jsalisburytisch, ok, I can start a bisect between -rc6 and -rc7.  It will require testing of about 7 - 10 test kernels.  Would you be able to test?19:04
tischsure, i'll be of as much help as i can.19:05
jsalisburytisch, I'll build the first kernel .  I'll post links to the test kernels in the bug report19:06
tischok, i'll grab the links from there and install and test those kernels19:07
jsalisburytisch, thanks19:07
tischthanks to you man!19:07
tischas is said, you're doing the heavy lifting compiling kernels here19:08
jsalisburytisch, its no problem at all19:08
CarlFKI likely did something wrong, but in case anyone wants a panic - pxe booted vmlinuz-4.10.0-19-generic.efi   https://veyepar.nextdayvideo.com/static/temp/pxe_efi_panic1.png20:07
tischjsalisbury: there is no linux-image-extra in http://kernel.ubuntu.com/~jsalisbury/lp1685865/82f1faa86727de976e38eade5e96a1846742d71e/ so ig uess i'll just download linux-headers*_amd64.deb and linux-image*_amd64.deb?20:15
jsalisburytisch, correct, that is a mainline kernel, so there is no -extra package.  You just need to install the linux-image pacakge.20:26
tischjsalisbury: ok, thanks. i'll also leave out the linux-image*_all.deb i guess?20:27
tischjsalisbury: sorry i meant linux-headers*_all.deb20:28
jsalisburytisch, correct.  you just need this file: linux-image-4.11.0-041100rc6-generic_4.11.0-041100rc6.201704241508_amd64.deb20:28
tischjsalisbury: thanks for the clarification. and sorry for me being not really literate about installing kernels20:31
jsalisburytisch, sure, no problem20:31
LocutusOfBorgthanks jsalisbury for the kernel help!20:56
LocutusOfBorgand sorry for not finding the right one :(20:56
LocutusOfBorgsigh maybe the culprit is c4a3fa261b16858416f1fd7db03a33d7ef5fc0b321:20

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