Re: [Xen-devel] [PATCH] Xen: Force non-irq keyhandler to be run in tasklet when receive a debugkey from serial port

["Lan, Tianyu" <tianyu.lan@xxxxxxxxx>]

On 10/24/2016 8:19 AM, Konrad Rzeszutek Wilk wrote:
> On Sat, Oct 22, 2016 at 07:23:03PM +0800, Lan Tianyu wrote:
> > __serial_rx() runs in either irq handler or timer handler and non-irq
> > keyhandler should not run in these contexts. So always force non-irq
> > keyhandler to run in tasklet when receive a debugkey from serial port
> If the machine is hung with an IRQ handler being stuck, and
> one does 'Ctrl-Ax3` followed by 'C' .. which would not be invoked
> (as it is not an IRQ handler??
If serial port's interrupt still works in this case, the 'C'
keyhandler kexec_crash() will be invoked in a tasklet. This behavior was
changed by my patches if includes this patch.


> > Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> > ---
> >  xen/drivers/char/console.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
> > index b0f74ce..184b523 100644
> > --- a/xen/drivers/char/console.c
> > +++ b/xen/drivers/char/console.c
> > @@ -347,7 +347,7 @@ static void switch_serial_input(void)
> >  static void __serial_rx(char c, struct cpu_user_regs *regs)
> >  {
> >      if ( xen_rx )
> > -        return handle_keypress(c, regs, !in_irq());
> > +        return handle_keypress(c, regs, true);
> >
> >      /* Deliver input to guest buffer, unless it is already full. */
> >      if ( (serial_rx_prod-serial_rx_cons) != SERIAL_RX_SIZE )
> > --
> > 2.9.3
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