Re: -current on armv7 stuck with flashing disk light
Date: Tue, 27 Jun 2023 17:16:57 UTC
On Tue, Jun 27, 2023 at 09:59:40AM -0700, Mark Millard wrote: > On Jun 27, 2023, at 09:47, Mark Millard <marklmi@yahoo.com> wrote: > > > On Jun 27, 2023, at 09:29, bob prohaska <fbsd@www.zefox.net> wrote: > > > >> On Mon, Jun 26, 2023 at 07:57:05PM -0700, Mark Millard wrote: > >>> On Jun 26, 2023, at 19:12, bob prohaska <fbsd@www.zefox.net> wrote: > >>> > >>>> A Pi2 freshly updated to > >>>> FreeBSD 14.0-CURRENT #41 main-c3e58ace31: Mon Jun 26 17:06:01 PDT 2023 > >>>> bob@www.zefox.com:/usr/obj/usr/src/arm.armv7/sys/GENERIC arm > >>>> got stuck with a flashing USB disk LED after starting a -j3 buildworld. > >>>> No response to debugger escape, had to pull the plug. > > > > I'm confused. > > > > That says "stuck with a flashing USB disk LED". But: > > > > http://nemesis.zefox.com/~bob/fbsd/rpi2/20230623/readme > > > > says: "the disk had gone to sleep mode. Both LEDs were off" > > > > Are these two different examples with variable behavior > > across the examples? > > Yes, I got mixed up. There have been several failures, some belated and the most recent one which was prompt (with a new kernel). > >>> If I understand right, the LED flashing means the disk > >>> had not stopped doing I/O: the system was still running, > >>> doing disk activity. (But I do not have a description > >>> of what your drive documentation says about how the > >>> drive handles the LED and what various patterns/colors > >>> may mean.) > >>> > >>> If the processes associated with processing input that > >>> would identify the debugger escape had the kernel stacks > >>> involved swapped out to swap space, I doubt that the > >>> debugger escape would work until/unless the kernel > >>> stacks are brought back into kernel RAM. > >>> > >>> Avoiding the specific way of losing control is why I > >>> have in /etc/sysctl.conf : > >>> > >>> # > >>> # Together this pair avoids swapping out the process kernel stacks. > >>> # This avoids processes for interacting with the system from being > >>> # hung-up by such. > >>> vm.swap_enabled=0 > >>> vm.swap_idle_enabled=0 > >>> > >> > >> This combination was tried and didn't seem to have any consistent > >> effect. It's commented out at the moment. > > > > By not having them, we have no way to know if the > > relevant kernel stacks had been moved to swap space. > > Having them is part of problem isolation/identification > > even when other forms of loss of control happen. > > > > The 2 lines serve more than one goal. > > > >>> (No claim such is the only way to lose control.) > >>> > >>> You might be able to get a clue if their was disk I/O going > >>> on based on modification times on files you know would have > >>> been modified periodically for some time (minutes) before > >>> you pulled the plug --but not modified on reboot and later > >>> activity. May be a log file that would only be modified by > >>> the build that you had been trying to do? > >>> > >> > >> There are log files for build and disk activity (for a cold > >> hang, no disk activity at all) at > >> http://nemesis.zefox.com/~bob/fbsd/rpi2/20230623/ > > > > So this is a different hangup? > > j4swapscript.log has internal timestamp pairs: > > Wed Jun 21 16:34:06 PDT 2023 > . . . > Fri Jun 23 07:26:10 PDT 2023 > > It would be interesting to know if "Jun 23 07:26:10" > was after the appearent hangup was identified vs. > before. > > >> In this case the top window was via ssh. Lately I've > >> taken to running top on the serial console in hopes > >> that will help distinguish system hangs from USB hangs. > > > > If you want to identify system hangs, please > > put back: > > > > vm.swap_enabled=0 > > vm.swap_idle_enabled=0 > > They're reinstated now, but I don't want to disturb the system while it seems to be building world acceptably. Sorry for mixing things up! bob prohaska