Garbled console output on Pi3

[bob prohaska]

On Fri, Mar 09, 2018 at 01:05:27PM -0800, Michael Mitchell (megabyte) wrote:
> This happens to me when the cable FTDI USB/232TTL isn't seated very well. Pin header connectors do have
> a limited cycle count, and become loose over time. The first thing I always blame is the cable...
> 
> Michael Mitchell
> 

I tried switching usb-serial adapters, in this case going from pl2303 to
ftdi-232. Didn't make any difference. On connection, the console output
looks fine. When I started up stress2 (as a regular, unpriviledged user)
the console started putting out

Mar  9 15:18:31 www kernel: ecsmedn tt hsrc2h epdid_ yi8e8l1d9
Mar  9 15:18:31 www kernel:  <3t>crmide d tthor 2u spei dn oi8d8 n1-9898 1pt9r9r iterdi etdo  tuessee nnto n-spcrheesde_nyti eslcdh
Mar  9 15:18:31 www kernel: d_ycimedl dt
Mar  9 15:18:31 www kernel: r2c mpdi dt hr828 1p9i9d  tr8i8e1d9 9ot  tursoiee  dnu ostneo-  unsoen -nporne-spernets enstc hsecdh_eydi_eylide
Mar  9 15:18:31 www kernel: d
Mar  9 15:18:31 www kernel: mdc mtdh rt2h rp2i dp id8 81898199 9t rtireide dt ot ou sues en onno-np-rperseesnetn tpsrce sheends_tyci ehlesddc_
Mar  9 15:18:31 www kernel: ield

In this particular case, the other four ssh sessions began to exhibit 
snippets of scrambled out put also, for example

Message from syslogd at www at Mar  9 15:18:31 ...
www kernel: rc2m d

and

last pid: 89780;  load averages: 16.42, 43.26, 23.613                       up 0+21:25:33  15:21:17
45 processes:  1 running, 40 sleeping, 4 zombie
CPU:  0.0% user,  0.0% nice,  1.3% system,  5.7% interrupt, 93.0% idle
Mem: 13M Active, 2868K Inact, 105M Wired, 12M Buf, 788M Free
Swap: 4096M Total, 34M Used, 4062M Free

Message from syslogd at www at Mar  9 15:18:31 ...ATE   C   TIME    WCPU COMMAND
88255 bob : rc2m d0c18d20tthr2 11128K   296K ufs     2   0:00   0.48% dirrename
88248 bob ldd_      1  20    0 11128K   296K ufs     1   0:00   0.47% dirrename
88253 bob           1  20    0 11128K   292K ufs     1   0:00   0.45% dirrename
88254 bob           1  20    0 11128K   292K biowr   1   0:00   0.45% dirrename
88256 bob           1  20    0 11128K   296K ufs     3   0:00   0.43% dirrename
88249 bob           1  20    0 11128K   292K ufs     1   0:00   0.42% dirrename
88252 bob           1  20    0 11128K   292K ufs     1   0:00   0.41% dirrename

also 

bob at www:/usr/src % 
Message from syslogd at www at Mar  9 15:16:06 ...
www kernel:  38 8t2r0i0e dt rtioe du stedo   nutoshner- 2pn ropeisde nn8t8 2-2psr3c hetesrdeinetd _ sytciohe eldd_

Message from syslogd at www at Mar  9 15:18:29 ...
www kernel: 83s2>c0cm8d  tthr2 pidd  t8o8 us208e  tnroine-dp rteos eunhseetd  nsocnh-epdr_eysieenltdr 

Message from syslogd at www at Mar  9 15:18:31 ...
www kernel: rc2m d

and finally, in the session where stress2 was running

15:15:20 Loop #1
      rw: run time  0+00:02:00, incarnations   8, load  70, verbose 1
    swap: run time  0+00:02:00, incarnations  30, load  80, verbose 1
 symlink: run time  0+00:02:00, incarnations  11, load  20, verbose 1
    thr2: run time  0+00:02:00, incarnations  13, load  20, verbose 1
   creat: run time  0+00:02:00, incarnations   9, load  80, verbose 1
dirrename: run time  0+00:02:00, incarnations   9, load  20, verbose 1

Message from syslogd at www at Mar  9 15:16:06 ...
www kernel:  38 8t2r0i0e dt rtioe du stedo   nutoshner- 2pn ropeisde nn8t8 2-2psr3c hetesrdeinetd _ sytciohe eldd_

Message from syslogd at www at Mar  9 15:18:29 ...
www kernel: 83s2>c0cm8d  tthr2 pidd  t8o8 us208e  tnroine-dp rteos eunhseetd  nsocnh-epdr_eysieenltdr 

Message from syslogd at www at Mar  9 15:18:31 ...
www kernel: rc2m d
20180309 15:21:32 creat.cfg, elapsed 00:06:14
Note: all.sh in stress2/misc is the preferred test to run.
     run: run time  0+00:05:00, incarnations   1, load 100, verbose 1
15:21:32 Loop #1
   creat: run time  0+00:02:00, incarnations   5, load 100, verbose 1

So, I don't think it's the usb-serial adapter....

Thanks for reading!

bob prohaska