Re: 2.6.2-rc2-bk1 oopses on boot (ACPI patch)

[Andrew Morton <akpm@osdl.org>]

Alessandro Suardi <alessandro.suardi@oracle.com> wrote:
>
> Already reported, but I'll do so once again, since it looks like
>   in a short while I won't be able to boot official kernels in my
>   current config...
> 
> Original report here:
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/0312.3/0442.html

Divide by zero.  Looks like ACPI is now passing bad values into the
frequency change notifier.

Does this make the oops go away?

diff -puN drivers/cpufreq/cpufreq.c~cpufreq-workaround drivers/cpufreq/cpufreq.c
--- 25/drivers/cpufreq/cpufreq.c~cpufreq-workaround	2004-01-27 18:36:05.000000000 -0800
+++ 25-akpm/drivers/cpufreq/cpufreq.c	2004-01-27 18:36:42.000000000 -0800
@@ -928,6 +928,11 @@ void cpufreq_notify_transition(struct cp
 		return;   /* Only valid if we're in the resume process where
 			   * everyone knows what CPU frequency we are at */
 
+	if (freqs->new == 0) {
+		printk("%s: avoiding div-by-zero\n", __FUNCTION__);
+		return;
+	}
+
 	down_read(&cpufreq_notifier_rwsem);
 	switch (state) {
 	case CPUFREQ_PRECHANGE:

_