Any chance you can get at the user-data-dir on the machine and haven't rebooted?

I have not rebooted since that crash, no. The device is in retail mode, though, so I'm not sure what user-data-dir files I can actually reach.  I've just submitted a feedback report, tagged with this bug #, if that helps?

Hi wez,
  What machine are you using ? Could you attach the feadkback report here?

This is a ChromeOS Panther device. I've uploaded several issue reports but I don't see them in my list of submitted reports; will check whether we expect them to be there or somewhere else...

Just hit this again.  I cannot see the feedback reports I filed previously, since they are routed to a project I'm not authorized for; will IM you the relevant link.

+haraken, since IIRC I have MemoryCoordinatorV0-Enabled in my Variations on this device.

The feedback is here
https://feedback.corp.google.com/product/208/neutron?lView=rd&lRSort=1&lROrder=2&lRFilter=1&lReportSearch=user:wez@google.com&lReport=51529190283

However I think the feedback is created after the crash, right ?

From the log swap is not heavily used
KiB Mem:   3986144 total,  3741100 used,   245044 free,    29976 buffers
KiB Swap:  3999996 total,   289688 used,  3710308 free.   894828 cached Mem

Also kswap0d doesn't consume too much CPU 
   26 root      20   0       0      0      0 S  6.1  0.0   0:09.52 kswapd0

Yes, the feedback is from immediately after the crash; it wouldn't be possible to gather feedback immediately before the crash because everything is janky, and about to crash.

Do these reports not include the previous chrome-user-log?

One other thing to look at. After this happens to you go to about:histograms and see if you have an entry for SessionCrashed.Bubble. If you do, what is it?

There is no entry for SessionCrashed.Bubble under chrome://histograms on
this device; however, I did log out and back in again this morning (which
lost my session state); so perhaps I would only expect that histogram to be
present after recovery from a crash?

That's right, the histogram only applies to the current session. If you see this again please bring up about:histograms immediately and take a look.

Just had this crash again and loaded histograms immediately after hitting Restore, and having the session fail to restore, but there was nothing in there with "Bubble" nor "SessionCrashed in it.

Crash had occurred shortly after waking the device after it had been idle over the weekend, and then switching to the second signed-in profile - crash occurred just before the other profile was displayed.

What's strange is that in /var/log/chrome I see three log files last modified around the time of the crash; one is a normal-looking 37KB log file, while the other two have log output from Chrome startup and then just stop.  I do have some flags set in about:flags; would that explain the two truncated logs?

Listing of my /var/log at present:

chrome                  1.7 kB	30/01/2017, 09:56:19
chrome_20170120-143629	53.9 kB	23/01/2017, 15:34:24
chrome_20170123-154029	17.8 kB	23/01/2017, 15:46:30
chrome_20170123-154640	35.4 kB	25/01/2017, 10:12:13
chrome_20170125-101705	27.6 kB	25/01/2017, 10:56:06
chrome_20170125-105611	18.0 kB	25/01/2017, 10:57:52
chrome_20170125-105803	34.9 kB	26/01/2017, 10:14:30
chrome_20170126-102043	3.8 kB	26/01/2017, 10:21:54
chrome_20170126-102213	37.2 kB	30/01/2017, 09:52:03
chrome_20170130-095609	1.8 kB	30/01/2017, 09:56:14
chrome_20170130-095616	1.7 kB	30/01/2017, 09:56:19

After the crash and you logged in you weren't presented with the restore infobar? I switched chromeos from infobar to bubble here: 653966, but that just landed, which includes the uma logs I mentioned.

I can't explain the truncated logs. Some one on the chromeos side can hopefully explain that.

Yes, I was presented with the restore infobar. I clicked it but it just
restored a single window with a New Tab Page, i.e. had no discernible
effect.

I have just had my ChromeOS system start to jank and then (Chrome) lock-up while playing a video (crash id: d5f751d580000000).

When Chrome re-started it briefly showed a new tab with the Restore option but the option disappeared after a second or so, so I lost my previous session state again.

Was the restore option an info-bar? I removed that here: https://codereview.chromium.org/2656213002 , and made the bubble *not* disappear automatically anymore here: https://codereview.chromium.org/2650293002 . The crash says you're at 57.0.2987.32, which has a position of 444943. The second patch I mentioned landed at 446146, so you wouldn't have seen them yet.

You should still be able to access the closed session at this point by restoring tabs, eg control-shift-T.

One option for chromeos is to show the bubble in ash some where, perhaps anchored to the tray.

Yes, this was an infobar. I didn't realise the Ctrl+Shift+T trick. :-/