Re: Arm v7 RPi2 -current unresponsive to debugger escape during buildworld

On Nov 24, 2025, at 18:07, bob prohaska <[email protected]> wrote:

> A few minutes ago a Pi2 running buildworld for -current locked up again, with no
> responsie to the debugger escape.
> 
> The system was swapping fairly hard but not stuck, maybe 600 MB in use, eventually
> swap use declined but in minutes it got stuck with top displaying:
> 
> last pid: 51520;  load averages:    2.82,    2.96,    2.96                     up 1+02:48:27  16:27:58
> 57 processes:  3 running, 54 sleeping
> CPU: 66.4% user,  0.0% nice, 16.0% system,  0.3% interrupt, 17.4% idle
> Mem: 183M Active, 540M Inact, 416K Laundry, 175M Wired, 98M Buf, 19M Free
> Swap: 2048M Total, 23M Used, 2025M Free, 1% Inuse
> 
>  PID USERNAME    THR PRI NICE   SIZE    RES STATE    C   TIME    WCPU COMMAND
> 51497 root          5  59    0   352M   208M uwait    3   0:08 161.51% ld.lld
> 51518 root          1 101    0   167M    71M CPU1     1   0:03  87.52% cc
> 51520 root          1  59    0   167M    72M RUN      2   0:03  67.88% cc
> 11811 root          1   0    0  6724K  1456K CPU0     0   5:51   0.46% top
> 2047 root          1   0    0  4676K   704K select   0   1:08   0.09% powerd
> 2206 bob           1   0    0    14M  1212K select   0   0:46   0.06% sshd-session
> 2119 root          1   9    0    14M  2320K select   1   1:27   0.00% sshd
> 
> The over-100% utilization for cpu 3 looks somewhat implausible.

It is very plausible based on the above: note that THR
(thread count) indicates 5 for ld.lld : It can have more
than one core in use at the same time part of the time
in order to have 161.51% WCPU. More than core 3 was in
use by ld.lld . Some of the information shown is likely
specific to the main/original thread.

(Top has a display mode that shows one thread per line
instead of one process per line. It can also display
Thread IDs instead of Process IDs. But PID can sometimes
make it easier to identify which threads are part of one
process. Non-thread-specific information is replicated.
Top can also display more of the command line text.)

> Might it suggest anything significant? I haven't seen this from 
> top in a long time, so relatively speaking it's new behavior. 
> 
> There were no console warnings of any kind.


===
Mark Millard
marklmi at yahoo.com