Re: panic running include/t_paths

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

On Mon, 4 May 2015, Manuel Bouyer wrote:

> Hello,
> since a few days, anita Xen tests of HEAD panics on
> include/t_paths:
> include/t_paths (42/618): 1 test cases
>    paths: uvm_fault(0xc15ef0dc, 0, 1) -> 0xe
> fatal page fault in supervisor mode
> trap type 6 code 0 eip c03ab50a cs 9 eflags 10246 cr2 0 ilevel 0 esp 4300
> curlwp 0xc17d1a80 pid 24550 lid 1 lowest kstack 0xcdb582c0
> panic: trap

<snip>

OK, I think I found this one!

It seems that when sysmonopen() is called, it might need to autoload the 
module that handles the specific sub-comopnent (envsys, power, or wdog). 
But if the autoload failed, the code blindly proceeded to call the 
sub-component's open routine anyway (indirectly through the sysmon_opvec 
table).  Since autoload had failed, the opvec entry was never loaded and 
we jumped off into never-never land.  :)

I've fixed the code to just return the error code ENODEV if autoload 
fails.

The include/t_paths test will likely still fail, since it won't be able 
to open /dev/{sysmon,power,wdog} paths.  But at least it shouldn't panic 
any more.


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