On Fri, Nov 27, 2015 at 12:09:30PM +0100, Petr Mladek wrote:
> What we can do, though, is to zap all printk locks. We already do this
> when a printk recursion is detected. This should be safe because
> the system is crashing and there shouldn't be any printk caller
> that would cause the deadlock.
On Tue 2015-12-01 23:44:37, Russell King - ARM Linux wrote:
> On Fri, Nov 27, 2015 at 12:09:30PM +0100, Petr Mladek wrote:
> > What we can do, though, is to zap all printk locks. We already do this
> > when a printk recursion is detected. This should be safe because
> > the system is crashing and t
On Fri, Dec 04, 2015 at 04:27:09PM +0100, Petr Mladek wrote:
> On Tue 2015-12-01 23:44:37, Russell King - ARM Linux wrote:
> > On Fri, Nov 27, 2015 at 12:09:30PM +0100, Petr Mladek wrote:
> > > What we can do, though, is to zap all printk locks. We already do this
> > > when a printk recursion is d
From: Russell King - ARM Linux
> Sent: 04 December 2015 17:13
...
> I have a slightly different view...
>
> > > I don't see bust_spinlocks() dealing with any of these locks, so IMHO
> > > trying to make this work in NMI context strikes me as making the
> > > existing solution more unreliable on AR
> Take the scenario where CPU1 is in the middle of a printk(), and is
> holding its lock.
>
> CPU0 comes along and decides to trigger a NMI backtrace. This sends
> a NMI to CPU1, which takes it in the middle of the serial console
> output.
>
> With the existing solution, the NMI output will be w
On Mon 2015-12-07 15:48:33, David Laight wrote:
> From: Russell King - ARM Linux
> > Sent: 04 December 2015 17:13
> ...
> > I have a slightly different view...
> >
> > > > I don't see bust_spinlocks() dealing with any of these locks, so IMHO
> > > > trying to make this work in NMI context strikes