Hi Daniel,
On Mon, Oct 09, 2017 at 02:04:40PM +0200, Daniel Lezcano wrote:
> On 04/09/2017 08:52, Leo Yan wrote:
> > After applied Stefan Wahren patch ("ARM: cpuidle: Avoid memleak if init
> > fail") there have no memleak issue, but the code is not consistent to
> > handle initialization failure between driver registration and device
> > registration. And when device registration fails, it misses to
> > unregister the driver.
> >
> > So this patch is to refine failure handling in init flow, it adds two
> > 'goto' tags: when register device fails, it goto 'init_dev_fail' tag and
> > free 'dev' structure and unregister driver; when register driver fails,
> > it goto 'init_drv_fail' tag and free 'drv' structure.
> >
> > Cc: Daniel Lezcano <daniel.lezc...@linaro.org>
> > Cc: Stefan Wahren <stefan.wah...@i2se.com>
> > Signed-off-by: Leo Yan <leo....@linaro.org>
> > ---
> > drivers/cpuidle/cpuidle-arm.c | 25 ++++++++++++++++---------
> > 1 file changed, 16 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
> > index 52a7505..f419f6a 100644
> > --- a/drivers/cpuidle/cpuidle-arm.c
> > +++ b/drivers/cpuidle/cpuidle-arm.c
> > @@ -86,10 +86,13 @@ static int __init arm_idle_init(void)
> >
> > for_each_possible_cpu(cpu) {
> >
> > + drv = NULL;
>
> ^^^^^
>
> This initialization is not needed.
Yeah.
> > + dev = NULL;
> > +
> > drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
> > if (!drv) {
> > ret = -ENOMEM;
> > - goto out_fail;
> > + goto init_drv_fail;
>
> Here we can jump directly to out_fail, no ?
Yes, can directly jump to out_fail.
> > }
> >
> > drv->cpumask = (struct cpumask *)cpumask_of(cpu);
> > @@ -104,13 +107,13 @@ static int __init arm_idle_init(void)
> > ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
> > if (ret <= 0) {
> > ret = ret ? : -ENODEV;
> > - goto init_fail;
> > + goto init_drv_fail;
>
> goto out_kfree_drv;
>
> > }
> >
> > ret = cpuidle_register_driver(drv);
> > if (ret) {
> > pr_err("Failed to register cpuidle driver\n");
> > - goto init_fail;
> > + goto init_drv_fail;
>
> goto out_unregister_drv;
Just want to check again, here should be "goto out_kfree_drv"?
> etc ...
>
> > return 0;
> > -init_fail:
> > +
> > +init_dev_fail:
> > + kfree(dev);
> > + cpuidle_unregister_driver(drv);
> > +
> > +init_drv_fail:
> > kfree(drv);
> > -out_fail:
> > +
>
> So, the code should end up with:
>
> out_kfree_dev:
> kfree(dev);
> out_unregister_drv:
> cpuidle_unregister_drv(drv);
> out_kfree_drv:
> kfree(drv);
Yeah, this is clearer than my patch :)
> > while (--cpu >= 0) {
> > dev = per_cpu(cpuidle_devices, cpu);
> > cpuidle_unregister_device(dev);
> >
>
> Perhaps it could nicer to create a function with the rollback embedded:
>
> for_each_possible_cpu(cpu) {
> ret = arm_idle_init_cpu(cpu)
> if (ret)
> goto out_fail;
> }
>
> return 0;
>
> out_fail:
>
> while (--cpu >= 0) {
> cpuidle_unregister_device(per_cpu(cpuidle_devices,cpu));
> cpuidle_unregister_driver(cpuidle_get_cpu_driver(dev));
> kfree(dev);
> kfree(drv);
> }
>
> return ret;
>
> And arm_idle_init_cpu(int cpu) does what is currently in the loop content.
Understood. I will split into two patches, one patch is to fix
resource releasing issue, the second patch is refactoring patch with a
'new function with the rollback embedded'.
Thanks a lot for the reviewing and suggestion.
Thanks,
Leo Yan
