Re: strange delays on console logouts (tty != 1)

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Sun, May 02, 2004 at 01:13:37AM -0700, Andrew Morton wrote:
> Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> >
> > On Sat, May 01, 2004 at 06:03:47PM -0700, Andrew Morton wrote:
> > > Petr Vandrovec <vandrove@vc.cvut.cz> wrote:
> > > >
> > > > (2) tty hangup is scheduled for work_queue.
> > > 
> > > This is the problem, isn't it?
> > > 
> > > >From what context is tty_hangup() invoked?  (stick a dump_stack() in there>?)
> > 
> > >From IRQ context.  It's tty_vhangup() which is invoked from user context,
> > and calls do_tty_hangup() synchronously.
> > 
> 
> But Chris and Petr are talking about virtual terminals on the local
> console, are they not?
> 
> If so, how is tty_hangup() getting involved?

The only way it could be invoked is via SAK, which obviously isn't
happening here.

However, login _does_ call sys_vhangup() which in turn calls tty_vhangup()
so I suspect that the statement "tty hangup is scheduled for work_queue"
is based on the _assumption_ that sys_vhangup() calls tty_hangup()
rather than the function it actually does.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core