Hi again, On Fri, Jun 26, 2020 at 05:50:00PM +0100, Steve McIntyre wrote: >On Fri, Jun 26, 2020 at 04:25:59PM +0200, Jann Horn wrote: >>On Fri, Jun 26, 2020 at 3:41 PM Greg KH <gre...@linuxfoundation.org> wrote: >>> On Fri, Jun 26, 2020 at 12:35:58PM +0100, Steve McIntyre wrote: > >... > >>> > Considering I'm running strace build tests to provoke this bug, >>> > finding the failure in a commit talking about ptrace changes does look >>> > very suspicious...! >>> > >>> > Annoyingly, I can't reproduce this on my disparate other machines >>> > here, suggesting it's maybe(?) timing related. >> >>Does "hard lockup" mean that the HARDLOCKUP_DETECTOR infrastructure >>prints a warning to dmesg? If so, can you share that warning? > >I mean the machine locks hard - X stops updating, the mouse/keyboard >stop responding. No pings, etc. When I reboot, there's nothing in the >logs. > >>If you don't have any way to see console output, and you don't have a >>working serial console setup or such, you may want to try re-running >>those tests while the kernel is booted with netconsole enabled to log >>to a different machine over UDP (see >>https://www.kernel.org/doc/Documentation/networking/netconsole.txt). > >ACK, will try that now for you. > >>You may want to try setting the sysctl kernel.sysrq=1 , then when the >>system has locked up, press ALT+PRINT+L (to generate stack traces for >>all active CPUs from NMI context), and maybe also ALT+PRINT+T and >>ALT+PRINT+W (to collect more information about active tasks). > >Nod. > >>(If you share stack traces from these things with us, it would be >>helpful if you could run them through scripts/decode_stacktrace.pl >>from the kernel tree first, to add line number information.) > >ACK.
Output passed through scripts/decode_stacktrace.sh attached. Just about to try John's suggestion next. -- Steve McIntyre, Cambridge, UK. st...@einval.com Dance like no one's watching. Encrypt like everyone is. - @torproject