Messages in this thread | | | Date | Fri, 29 Apr 2016 02:44:40 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] cpu/hotplug: handle unbalanced hotplug enable/disable |
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On Thu, 28 Apr 2016, Lianwei Wang wrote: > On Wed, Apr 27, 2016 at 11:15 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > > On Wed, 27 Apr 2016, Lianwei Wang wrote: > >> Yes. In our project, there is a kernel driver which register a pm > >> notifier. On some conditions this pm notifier will return an error and > >> abort the suspend process. The counter will be unbalanced in case it > >> happened. > > > > So what? You wreckaged your driver, so you fix it and be done with it. > > Do you mean no pm_notifier callback can return an error or NOTIFY_BAD > to abort the suspend process? > > It's not the driver issue. The driver return an error to abort the > suspend process on purpose. Why do you think it is not allowed to > return an error to abort suspend? > > The issue is very clear as described below. > 1. How the issue happened? > One of the pm notifier return error to abort suspend before > cpu_hotplug_disable() is called on PM_SUSPEND_PREPARE. > > 2. What's the result? > CPU hotplug work in a wrong way, or it doesn't work anymore. No way to > recover it. > > 3. The root cause is that there is no any handling for the unbalanced > cpu_hotplug_disable/enable calling. This patch add a protection for > such issue.
Wrong. This is the symptom. The root cause is in #1. Therefor you are trying to fix the symptom and not the root cause
> Anything not clear?
No.
I completely understand that you are tyring to put the cart before the horse.
Thanks,
tglx
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