problem with system freeze

[Goetz Isenmann]

Hi!

My problem started many weeks ago, with a cheap amd64 system running
i386 dfly240 and after updating to something (I believe) between
2.5.1.750 and 850, and any later version. The system stopped suddenly
responding to the keyboard and the mouse. As far as I remember, it only
happened within X11, and maybe only while also using the network. For
example restarting firefox with 10-20 open tabs often ended with a
freeze.

The same hardware is now running x86_64 v2.6.3.2.gdda6b-RELEASE
GENERIC+SMP and I just saw the same problem again. Sadly I am neither
able to interact with the system after a freeze nor do I find any
relevant information after restart, besides some hammer cleanup:

HAMMER(ROOT) recovery check seqno=011afb3f
HAMMER(ROOT) recovery range 3000000003147fb8-300000000314f498
HAMMER(ROOT) recovery nexto 300000000314f498 endseqno=011afbd9
HAMMER(ROOT) recovery undo  3000000003147fb8-300000000314f498 (29920 bytes)(RW)
HAMMER(ROOT) Found REDO_SYNC 30000000030d4200
HAMMER(ROOT) recovery complete
HAMMER(ROOT) recovery redo  3000000003147fb8-300000000314f498 (29920 bytes)(RW)
HAMMER(ROOT) Find extended redo  30000000030d4200, 474552 extbytes
HAMMER(ROOT) End redo recovery

Any ideas, what I could do before or after it happens the next time,
that might give my some info what's going on?