Re: About the fixes of /drivers/serial/8250.C in 2.6.17-rc6 foravoiding habbg-up

From: Alan Cox
Date: Mon Jun 19 2006 - 05:07:00 EST


Ar Llu, 2006-06-19 am 12:03 +0900, ysgrifennodd gouji:
> In /drivers/serial/8250.C of 2.6.17-rc6,
>
> these fixes are adapted for avoinding the problem of hang-up
> while TTY write and console write from kernel conflicted.

Yes, there is a bug in this version that was not in the one I submitted,
someone added an improvement.

> + if (oops_in_progress) {
> + locked = spin_trylock_irqsave(&up->port.lock, flags);
> + } else
> + spin_lock_irqsave(&up->port.lock, flags);
> +

It could always use spin_trylock_irqsave(). The oops in progress
optimisation makes some sense initially but there are many console
printk users that can occur during serial I/O in exceptional cases.

It's not an easy problem to solve with the current serial locking.

Alan

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