Comment # 4 on bug 1186332 from Coly Li

(In reply to Coly Li from comment #3)
> (In reply to Petr Tesa������������k from comment #0)
> > Created attachment 849559 [details]
> > dmesg after lockup
> > 
> > I've just experienced a kernel stall on my Lenovo Thinkpad X270, attached.
> > 
> > At this point I have no idea how to proceed, and no, I cannot reproduce the
> > hang at will.
> 
> The information is very limited. I understand there is no more stack trace,
> and I can only guess what happened.
> 
> I see one fix is about using an encrypted swap device, do you encrypt the
> swap partition ?

I see some suspicious and necessary fixes from dm-crypt deadlocking.

commit 528b16bfc3ae ("dm crypt: Avoid percpu_counter spinlock contention in
 crypt_page_alloc()")
commit c87a95dc28b1 ("dm crypt: defer decryption to a tasklet if interrupts
disabled")
commit a666e5c05e7c ("dm: fix deadlock when swapping to encrypted device")

Let me try to do the backport.

Coly Li