On Wed, 30 Jan 2008 11:21:49 +0100 "Remy Bohmer" <[EMAIL PROTECTED]> wrote:
> > > * Drop the lock here since it might end up calling > > > * uart_start(), which takes the lock. > > > spin_unlock(&port->lock); > > > */ > > > tty_flip_buffer_push(port->info->tty); > > > /* > > > spin_lock(&port->lock); > > > */ > > > The same code with this comments out runs > > I expect the UART generating the problem is the DBGU port. The DBGU > shares its interrupt line with the timer interrupt with the IRQF_TIMER > flag set, and thus the DBGU interrupt handler is running in > IRQF_NODELAY context. Within this context it is forbidden to lock a > normal spinlock, because a normal spinlock is converted to a mutex on > Preempt-RT; a mutex can sleep which is forbidden in interrupt context. > So, to get around this problem, this lock spinlock has to be of the > raw_spinlock_t type. The raw_spinlock_t is the normal mainline-kernel > spinlock, and as such it is not converted to a mutex, and will > therefor never sleep. > > Attached a patch that changes this spinlock type. I used it in my > patchset, but your updates of December last year do not need this > patch anymore, so apparantly you changed something that has a > regression on Preempt-RT... The code above is from the tasklet, so I don't think that's the problem. The interrupt handler doesn't take any locks. Or are spinlocks not allowed in softirq context either? > I believe I have to look at the latest set of patches, and try to find > any regressions. Do you have a location somewhere where I can download > the latest versions? Or do I need to dig through LKML to find the > latest... ;-) They are in -mm. You were Cc'ed I think... Haavard Haavard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
