Log Analyzer found "NOTREACHED()" and "TPM error 0x21".

Does it ever crash after a freeze? Can you supply some crash ids from chrome://crashes 

I think that's how I'd (better) describe the issue.  I'll just be doing
whatever and the everything on the screen will freeze and the mouse will
stop responding.  If there is any audio then the last sound produced before
the freeze will continue being produced until the computer finally
reboots.  So maybe the best way to describe it would be a full system
freeze followed shortly be a reboot.  I've included crash IDs below (and
attached).
After following the Provide additional details link I decided not to create
a new issue but I thought I'd include the version from there:

Chrome Version: 56.0.2924.67Operating System: Linux 3.10.18

Crashes
Start uploading crashes
Crashes (3)
Crash ID Chrome (Server ID: a8f9a14680000000)

Automatically reported Wednesday, January 25, 2017 at 5:59:36 AM

Provide additional details
<https://code.google.com/p/chromium/issues/entry?template=Crash%20Report&comment=IMPORTANT%3A%20Your%20crash%20has%20already%20been%20automatically%20reported%20to%20our%20crash%20system.%20Please%20file%20this%20bug%20only%20if%20you%20can%20provide%20more%20information%20about%20it.%0A%0A%0AChrome%20Version%3A%2056.0.2924.67%0AOperating%20System%3A%20Linux%203.10.18%0A%0AURL%20(if%20applicable)%20where%20crash%20occurred%3A%0A%0ACan%20you%20reproduce%20this%20crash%3F%0A%0AWhat%20steps%20will%20reproduce%20this%20crash%3F%20(If%20it%27s%20not%20reproducible%2C%20what%20were%20you%20doing%20just%20before%20the%20crash%3F)%0A1.%0A2.%0A3.%0A%0A****DO%20NOT%20CHANGE%20BELOW%20THIS%20LINE****%0ACrash%20ID%3A%20crash%2Fa8f9a14680000000&labels=Restrict-View-EditIssue%2CStability-Crash%2CUser-Submitted>
Crash ID Chrome (Server ID: 82429d8880000000)

Automatically reported Monday, January 23, 2017 at 9:08:50 PM

Provide additional details
<https://code.google.com/p/chromium/issues/entry?template=Crash%20Report&comment=IMPORTANT%3A%20Your%20crash%20has%20already%20been%20automatically%20reported%20to%20our%20crash%20system.%20Please%20file%20this%20bug%20only%20if%20you%20can%20provide%20more%20information%20about%20it.%0A%0A%0AChrome%20Version%3A%2056.0.2924.67%0AOperating%20System%3A%20Linux%203.10.18%0A%0AURL%20(if%20applicable)%20where%20crash%20occurred%3A%0A%0ACan%20you%20reproduce%20this%20crash%3F%0A%0AWhat%20steps%20will%20reproduce%20this%20crash%3F%20(If%20it%27s%20not%20reproducible%2C%20what%20were%20you%20doing%20just%20before%20the%20crash%3F)%0A1.%0A2.%0A3.%0A%0A****DO%20NOT%20CHANGE%20BELOW%20THIS%20LINE****%0ACrash%20ID%3A%20crash%2F82429d8880000000&labels=Restrict-View-EditIssue%2CStability-Crash%2CUser-Submitted>
Crash ID ChromeOS (Server ID: 82fde6e580000000)

Automatically reported Saturday, January 21, 2017 at 8:30:22 PM

Provide additional details
<https://code.google.com/p/chromium/issues/entry?template=Crash%20Report&comment=IMPORTANT%3A%20Your%20crash%20has%20already%20been%20automatically%20reported%20to%20our%20crash%20system.%20Please%20file%20this%20bug%20only%20if%20you%20can%20provide%20more%20information%20about%20it.%0A%0A%0AChrome%20Version%3A%2056.0.2924.67%0AOperating%20System%3A%20Linux%203.10.18%0A%0AURL%20(if%20applicable)%20where%20crash%20occurred%3A%0A%0ACan%20you%20reproduce%20this%20crash%3F%0A%0AWhat%20steps%20will%20reproduce%20this%20crash%3F%20(If%20it%27s%20not%20reproducible%2C%20what%20were%20you%20doing%20just%20before%20the%20crash%3F)%0A1.%0A2.%0A3.%0A%0A****DO%20NOT%20CHANGE%20BELOW%20THIS%20LINE****%0ACrash%20ID%3A%20crash%2F82fde6e580000000&labels=Restrict-View-EditIssue%2CStability-Crash%2CUser-Submitted>

There are just now two more.  Not sure what caused them, I don't recall
experiencing any issues at these times.

Crash ID Chrome (Server ID: e915821580000000)

Automatically reported Thursday, January 26, 2017 at 10:00:19 PM
Crash ID Chrome (Server ID: 2085821580000000)

Automatically reported Thursday, January 26, 2017 at 9:57:19 PM


Also I'm not completely sure there is a crash report for every instance of
the computer freezing and rebooting.  I only enabled crash reports somewhat
recently.

I wanted to add a couple things here.  I have a more recent debug log attached.  I also have a picture of the active chrome://net-internals/#events.  I had khan academy up at the time.  I don't know if the debug logs capture this data (and I haven't looked into it) and I thought it might be useful. Below are new Crash IDs, though there is probably one from January 28th (just a few minutes ago) that I don't have yet.

Crash ID Chrome (Server ID: 62a2d61580000000)

Automatically reported Friday, January 27, 2017 at 7:11:56 PM

Crash ID Chrome (Server ID: 725f43c880000000)

Automatically reported Friday, January 27, 2017 at 7:02:42 PM

Deleted: IMG_20170127_180214.jpg 4.6 MB

	IMG_20170127_180214.jpg 4.6 MB View Download

Deleted: debug-logs_20170128-165059.tgz 1.8 MB

debug-logs_20170128-165059.tgz 1.8 MB Download

From c#4 "So maybe the best way to describe it would be a full system
freeze followed shortly be a reboot." Looks like a kernel issue

I was running the beta channel at the time, I switched to the production
channel and the issue doesn't seem to present itself there.

Issue has not been modified or commented on in the last 365 days, please re-open or file a new bug if this is still an issue.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot