On Tue, Oct 17, 2017 at 09:35:39PM +0200, Mario Theodoridis wrote: > On 16.10.2017 05:37, James Cameron wrote: > >On Sun, Oct 15, 2017 at 06:21:36PM +0200, Mario Theodoridis wrote: > >>Thanks for the pointers, James. > >> > >>On 12.10.2017 23:24, James Cameron wrote: > >>>There's a good chance this problem has been fixed already. You > >>>are using a v4.4 kernel with many patches applied by Ubuntu. Here, we > >>>are more concerned with the latest kernels, and v4.4 is quite old. > >>> > >>>Please test some of the later kernels, see > >>>https://wiki.ubuntu.com/Kernel/MainlineBuilds > >>> > >>>In particular, test v4.13 or v4.14-rc4. > >> > >>I'm having a hard time with that, because the virtualbox-dkms build fails > >>with the 4.13 kernel, and virtualbox unfortunately is essential. > > > >Is virtualbox essential for reproducing the problem, or essential for > >your general use? > > It is essential for general use, like Internet connectivity. Okay, good, that means we can ignore virtualbox, and leave that to you. Please test v4.13 or v4.14-rc5, ignoring virtualbox for the time being. > >If the former, then that's interesting. > > > >If the latter, then you might instead test the v4.13 or v14-rc4 > >kernels for only the problem, and then revert to an older kernel after > >testing. > > > >Either way, to use virtualbox-dkms with a later kernel you may be able > >to upgrade just the virtualbox packages from a later Ubuntu release. > > > >See https://packages.ubuntu.com/virtualbox-dkms and > >https://packages.ubuntu.com/virtualbox for the later versions available. > > > >Purpose of the test can be to help isolate the cause, not only to > >solve your problem. > > Thanks for the info. > > > > >[...] > >You might also try with later firmware package. > >See https://packages.ubuntu.com/linux-firmware > > > >You might also test with booting installation media in live-mode, > >ignoring the internal disk. > > Ok, that was completely off the radar. Updating linux-firmware may run different firmware on the wireless card, and the change in behaviour may fix the problem. A gamble. A test with later installation media is useful, because you can verify problems with different kernels and wireless firmware without change to configuration. You might try Ubuntu 17.10 Artful ISO. > I ended up going the other way. I still had a 4.4.0-79-generic kernel and > booted that. It does not have this problem. > After checking out > git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/xenial > i tried to find the culprit but was not able to trace the back trace to a > potential null pointer or some such. I got stuck at > iwl_mvm_send_cmd_pdu_status not finding a reference to iwl_mvm_disable_txq > from there. > > I did got the following diff though > > git diff Ubuntu-4.4.0-79.100 Ubuntu-4.4.0-93.116 -- > drivers/net/wireless/iwlwifi/ drivers/net/wireless/mac80211_hwsim.c > > wifi.patch > > I don't know whether this came from upstream or was ubuntu sourced. Upstream. You found your problem was introduced in an Ubuntu kernel, in the update from -79 to -93. This contained Ubuntu backports of two stable kernel patches, which are also upstream patches; 8fbcfeb8a9cc ("mac80211_hwsim: Replace bogus hrtimer clockid") from v4.4.69 50ea05efaf3b ("mac80211: pass block ack session timeout to to driver") from v4.4.77 git log Ubuntu-4.4.0-79.100..Ubuntu-4.4.0-93.116 -- \ drivers/net/wireless/iwlwifi/ drivers/net/wireless/mac80211_hwsim.c git remote add stable \ git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git git fetch stable git log v4.4.68..v4.4.92 -- \ drivers/net/wireless/iwlwifi/ drivers/net/wireless/mac80211_hwsim.c > This fixed the issue for now, but now i'm stuck on that kernel :( Yes. Here in upstream, we would run the latest kernel v4.13 and work to fix that. Trouble you had with virtualbox packages would be eventually solvable, but aren't really a problem with the kernel itself. So your next step may be to report an Ubuntu bug, and say that -79 worked fine, and -93 did not. > While i'm perfectly comfortable with user land C, i have no kernel > experience (clue stick links definitely welcome). You might verify the above patches caused the problem by doing a bisection between -79 and -93. https://wiki.ubuntu.com/Kernel/KernelBisection Or by reverting only those patches. Then report to Ubuntu which patch caused the problem. > [...] Hope that helps. -- James Cameron http://quozl.netrek.org/
