Re: Re: [PATCH] spi: tegra20-slink: Fix runtime PM imbalance on error
From: Andy Shevchenko
Date: Fri May 22 2020 - 11:23:07 EST
On Fri, May 22, 2020 at 6:20 PM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
> On Fri, May 22, 2020 at 10:46 AM <dinghao.liu@xxxxxxxxxx> wrote:
...
> Moreover, consider below case
>
> CPU1: ...somewhere in the code...
> pm_runtime_get() // with success!
> ...see below...
> pm_runtime_put()
>
> CPU2: ...on parallel thread...
> ret = pm_runtime_get_sync() // failed!
> if (ret)
> pm_runtime_put() // oi vei, we put device into sleep
>
> So, there is a potential issue.
...and even if it's impossible (no bugs in runtime PM core, etc) the
code with put() looks suspicious.
--
With Best Regards,
Andy Shevchenko