* Miklos Szeredi <miklos@szeredi.hu> wrote:

quoted text
> On some strange workload involving strace and fuse I get ocasional 
> long periods (10-100s) of total unresponsiveness, not even SysRq-* 
> working.  Then the machine continues as normal.  Nothing in dmesg, 
> absolutely no indication about what is happening.

quoted text
> Any ideas?  Possibly something ACPI related?

how reproducable are these lockups - could you possibly trace it? If yes 
then please apply:

  http://www.tglx.de/private/tglx/ht-debug/tracer.diff

and run the attached trace-it-1sec.c thing in a loop:

  echo 1 > /proc/sys/kernel/mcount_enabled

  while true; do
     ./trace-it-1sec > trace-`date`.txt
  done

and wait for the lockup. Once it happens, please upload the trace*.txt 
file that contains the lockup, i guess we'll be able to tell you more 
about the nature of the lockup. (Perhaps increase the sleep(1) to 
sleep(5) to capture longer periods and to increase the odds that you 
catch the lockup while the utility is tracing.)

	Ingo