Thanks for making these efforts to debug this. Ketan: can we try replace
the one BUG_ON with two WARN_ON  to confirm the exact faulty condition? I
wish I can do that myself but I don't have a box at hand.

Yuchung

On Sun, Jan 13, 2013 at 1:39 PM, Felix Fietkau <nbd@openwrt.org> wrote:

> On 2013-01-13 7:03 PM, Eric Dumazet wrote:
> > I suspect a bug in the spin_is_locked() implementation on your arch, as
> > he socket lock should be held at this point.
> I don't think this is an arch implementation bug, this probably happens
> on all !SMP systems. See this bit from include/linux/spinlock_up.h:
>
> #define arch_spin_is_locked(lock)   ((void)(lock), 0)
>
> - Felix
>
>