Re: [debug patch] printk: Add a printk killswitch to robustify NMIwatchdog messages

From: Peter Zijlstra
Date: Mon Jun 06 2011 - 09:12:31 EST


On Mon, 2011-06-06 at 15:10 +0200, Ingo Molnar wrote:


> diff --git a/kernel/printk.c b/kernel/printk.c
> index 3518539..1b9d2be 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -859,7 +859,6 @@ asmlinkage int vprintk(const char *fmt, va_list args)
> zap_locks();
> }
>
> - lockdep_off();

At the very least you should also do: s/raw_local_irq_/local_irq/ on
this function.

> spin_lock(&logbuf_lock);
> printk_cpu = this_cpu;
>
> @@ -947,7 +946,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
> * Try to acquire and then immediately release the
> * console semaphore. The release will do all the
> * actual magic (print out buffers, wake up klogd,
> - * etc).
> + * etc).
> *
> * The console_trylock_for_printk() function
> * will release 'logbuf_lock' regardless of whether it
> @@ -956,7 +955,6 @@ asmlinkage int vprintk(const char *fmt, va_list args)
> if (console_trylock_for_printk(this_cpu))
> console_unlock();
>
> - lockdep_on();
> out_restore_irqs:
> raw_local_irq_restore(flags);
>

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