Re: [crash] kernel BUG at drivers/cpufreq/cpufreq.c:1060!

Dave Jones
2007-12-12T18:19:31Z

On Wed, Dec 12, 2007 at 11:40:13AM -0500, Dave Jones wrote:

> > powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ processors (1 cpu cores) (version 2.20.00)
> > powernow-k8: BIOS error - no PSB or ACPI _PSS objects
> > ------------[ cut here ]------------
> > kernel BUG at drivers/cpufreq/cpufreq.c:1060!
>
> The actual BUG you hit is
>
> if (unlikely(lock_policy_rwsem_write(cpu)))
> BUG();
>
> It _looks_ like we're leaking a refcount on that lock, but
> I don't see where. It's a shame you can't reproduce this easily,
> as cpufreq.debug=7 would give us more clues.
> (And CONFIG_CPUFREQ_DEBUG=y)

So we're missing some unlocks in some error paths.
It's feasible you hit one of those.
This patch should be the fix for that.

Dave

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 5e626b1..79581fa 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -841,19 +841,25 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
drv_attr = cpufreq_driver->attr;
while ((drv_attr) && (*drv_attr)) {
ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
- if (ret)
+ if (ret) {
+ unlock_policy_rwsem_write(cpu);
goto err_out_driver_exit;
+ }
drv_attr++;
}
if (cpufreq_driver->get){
ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
- if (ret)
+ if (ret) {
+ unlock_policy_rwsem_write(cpu);
goto err_out_driver_exit;
+ }
}
if (cpufreq_driver->target){
ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
- if (ret)
+ if (ret) {
+ unlock_policy_rwsem_write(cpu);
goto err_out_driver_exit;
+ }
}

spin_lock_irqsave(&cpufreq_driver_lock, flags);
--