Page fault in IFNET_WLOCK_ASSERT [if.c and pccbb.c]

[Harsha]

Hi Robert,

Apologies for not getting earlier.

On Mon, Oct 12, 2009 at 6:46 AM, Robert N. M. Watson
<rwatson at freebsd.org> wrote:
>
> Looks like a NULL pointer dereference, so perhaps a more traditional bug --
> could you convert ifindex_alloc_locked+0x71 to a line of code? You can do
> this using kgdb on the kernel symbols file, perhaps "l
> *ifindex_alloc_locked+0x71".
It is the for loop in ifindex_alloc_locked() function-
 for (idx = 1; idx <= V_if_index; idx++)

idx is a local variable, so I figured it is V_if_index is what is
causing the page fault. It does look like a NULL pointer reference - I
see that V_if_index comes from that  vnet instance's value and uses
the macro VNET_VNET_PTR() down the chain. Since the call chain is
coming from a new thread cbb_event_thread, I believe that this
thread's vnet context needs to be set using CURVNET_SET().

I'll try this tomorrow, but if think I'm not on the right track or
want me to try something else please let me know.

Many thanks,
Harsha