Rich Freeman posted on Sun, 25 Sep 2016 09:55:42 -0400 as excerpted:

On Fri, Sep 23, 2016 at 12:58 AM, Duncan [off-list ref] wrote:

quoted

Btrfs raid1 you say, and you have existing compressed files it's trying
to read in the backtrace?

Sounds like the issues I see sometimes and have posted about where
after a crash that resulted in one device of my raid1 pair getting
behind the other, the kernel will crash if it sees too many
csum-errors, even tho it's /supposed/ to check the other copy and read
from it if valid (which it is as a btrfs scrub resolves the issue).

When booted to rescue/single-user mode, can you run a scrub?

After a few reboots trying to capture the initial panic message (even
when I set panic_on_oops=1 I was getting multiple ones with only the
tainted one staying on screen), the system managed to stay up.  I
completed a scrub and it found no errors.

Well, so much for that theory.  If it found and fixed errors you'd likely 
be seeing the same problem I see sometimes, but if it didn't find any to 
fix... unlikely.

-- 
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"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman