Re: linux hangs with printk on schedule()

From: Robert Love (rml@tech9.net)
Date: Mon Feb 03 2003 - 19:43:52 EST


On Mon, 2003-02-03 at 19:35, Haoqiang Zheng wrote:

> I found Linux hangs when printk is inserted to the function schedule().
> Sure, it doesn't make much sense to add such a line to schedule(). But Linux
> shouldn't hang anyway, right? It's assumed that printk can be inserted
> safely to anywhere. So, is it a bug of Linux?

Its a known deadlock in 2.4:

        schedule -> printk() -> dmesg output -> klogd wakes up -> repeat

It is not a hard fix and its basically one of a few places where you
cannot call printk(), which is otherwise a very robust funciton.

        Robert Love

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Fri Feb 07 2003 - 22:00:13 EST