On Wednesday, June 18, 2014 11:27:32 AM Aaron Plattner wrote:
> Commit bd0fa9bb455d introduced a failure path to cpufreq_update_policy() if
> cpufreq_driver->get(cpu) returns NULL. However, it jumps to the 'no_policy'
> label, which exits without unlocking any of the locks the function acquired
> earlier. This causes later calls into cpufreq to hang.
>
> Fix this by creating a new 'unlock' label and jumping to that instead.
>
> v2: Delete the no_policy label and just return early if policy is NULL.
>
> Fixes: bd0fa9bb455d ("cpufreq: Return error if ->get() failed in
> cpufreq_update_policy()")
> Link:
> https://devtalk.nvidia.com/default/topic/751903/kernel-3-15-and-nv-drivers-337-340-failed-to-initialize-the-nvidia-kernel-module-gtx-550-ti-/
> Cc: Viresh Kumar <viresh.ku...@linaro.org>
> Cc: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> Signed-off-by: Aaron Plattner <aplatt...@nvidia.com>
Applied, thanks!
> ---
> v1 of this was tested by the user affected by the problem, but I don't have
> his
> email address so I can't add it as a Tested-by line.
>
> drivers/cpufreq/cpufreq.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index aed2b0cb83dc..62259d27f03e 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2242,10 +2242,8 @@ int cpufreq_update_policy(unsigned int cpu)
> struct cpufreq_policy new_policy;
> int ret;
>
> - if (!policy) {
> - ret = -ENODEV;
> - goto no_policy;
> - }
> + if (!policy)
> + return -ENODEV;
>
> down_write(&policy->rwsem);
>
> @@ -2264,7 +2262,7 @@ int cpufreq_update_policy(unsigned int cpu)
> new_policy.cur = cpufreq_driver->get(cpu);
> if (WARN_ON(!new_policy.cur)) {
> ret = -EIO;
> - goto no_policy;
> + goto unlock;
> }
>
> if (!policy->cur) {
> @@ -2279,10 +2277,10 @@ int cpufreq_update_policy(unsigned int cpu)
>
> ret = cpufreq_set_policy(policy, &new_policy);
>
> +unlock:
> up_write(&policy->rwsem);
>
> cpufreq_cpu_put(policy);
> -no_policy:
> return ret;
> }
> EXPORT_SYMBOL(cpufreq_update_policy);
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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