On 05.06.2011 13:36, Ingo Molnar wrote:
* Ingo Molnar<mingo@xxxxxxx> wrote:If the ticks stop this suggests a lockup within the printk code. [...]In which case the printk-killswitch patch below (to be applied *instead* of the previous debugging patch i sent) should provide the desired NMI watchdog output on the serial console. Warning: it's entirely untested.
How is the output supposed to come through? shouldn't printk revert to early_printk instead of just returning?
Note, since this is an SMP box, if the lockup messages show up with this patch but are mixed up with each other then adding a spinlock around the WARN() would probably help keeping the output serialized. A simple: static DEFINE_SPINLOCK(watchdog_output_lock); ... spin_lock(&watchdog_output_lock); ... [ the WARN_ON() logic. ] ... spin_unlock(&watchdog_output_lock); ... would suffice. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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