Re: vxWorks 6.7 tNet0 task crashed with fage fault: help needed from vxWorks guru

["Steven M. Hartman" <hartmansm@ornl.gov>]

Matthias Clausen wrote:

> Good idea - we got a hint from the hardware vendor that there might be a 
> vxWorks 6.7 "SMP Perfomance Patch" which should solve 'similar' 
> problems. - We'll check with WRS.
> Strange enough that they did not mention this to us...
> > 2) Also look for vxWorks 6 patches which could be installed.

Hello Matthias--

The "Page Fault Addr : 0x00000000" looks very suspicious. Null 
pointer somewhere? Strange that is is occurring in what looks to 
be deep within tNetTask.

I would second the suggestion to apply recommended patches for 
6.7. We started putting VxWorks 6.7 into production during our 
summer maintenance period (~8 IOCs so far), so the longest running 
production IOC with this version is less then 2 months uptime. But 
we have not seen any such problems in testing or production. We do 
have all WRS recommended patches as of July 9 (from trying to 
debug a geiEnd driver problem for the mv5500, fixed in 6.8 by the 
way).

> Unfortunately all of the network diagnostics do not work after a crash 
> of the net task.
> The shell will be blocked and no more diagnostics are possible.

We saw this before with 5.5 and it does make it very difficult to 
debug. In our case, memory corruption was occurring from another 
task writing beyond a malloc'd buffer, clobbering the meta data 
and making a mess of the free list. That task would end up 
suspended during either a malloc or free, so it ended up holding 
the semaphore protecting malloc/free. Apparently, tnetTask (at 
least in 5.5) does lots of malloc/free so we would find the 
suspended task promoted to priority 50 with tnetTask waiting on it 
to get the semaphore (and thus no network). The console shell 
would work, but a number of the show routines also use malloc. If 
you use any of those, the shell ends up blocking on the same 
semaphore and your only option is a reboot.

Does 'i' show anything promoted to a higher priority for you?


--
Steven Hartman
hartmansm@ornl.gov || 865-466-6473