Re: [1/3] OSF: code beautification.

["Pavel A. Nekrasov" <pnekras@gmail.com>]

it seems that I forgot to reply to the mailling list...

On 6/1/05, Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> On Wed, 1 Jun 2005 02:57:31 +0400
> Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> 
> > On Wed, 1 Jun 2005 00:37:05 +0200
> > "Pavel A. Nekrasov" <pnekras@gmail.com> wrote:
> 
> ...
> 
> > > BTW, fix a deadlock. match() can be called from both bh and process context.
> >
> > Neither it suffers rcu lock in nf_hook_slow()?
> 
> Ugh, it is read lock, but OSF match() method can be safely
> interrupted and reentered. BH are disabled when broadcasting over netlink,
> reading finger table is guarded by read_lock, while modification
> can be done only in process context which uses write_lock_bh().

not talking about netlink

say a program does send() running on you machine, so some packets can
hit match() from process context. While holding read lock, match() is
interrupted to handle a bh. now say, a packet coming from bh context
hits match() and tries to gets read lock but it's already held by the
packet coming from process context. deadlock.

kind regards,
Pavel