Re: [PATCH 2/2] PM / Domains: Avoid infinite loops in attach/detach code

From: Geert Uytterhoeven
Date: Tue Jun 23 2015 - 03:16:33 EST

Hi Rafael,

On Tue, Jun 23, 2015 at 1:41 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> On Monday, June 22, 2015 09:31:22 AM Geert Uytterhoeven wrote:
>> If pm_genpd_{add,remove}_device() keeps on failing with -EAGAIN, we end
>> up with an infinite loop in genpd_dev_pm_{at,de}tach().
>> This may happen due to a genpd.prepared_count imbalance. This is a bug
>> elsewhere, but it will result in a system lock up, possibly during
>> reboot of an otherwise functioning system.
>> To avoid this, put a limit on the maximum number of loop iterations,
>> including a simple back-off mechanism. If the limit is reached, the
>> operation will just fail. An error message is already printed.
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> This was too late for my first 4.2 pull request, but I may push it in the
> second half of the merge window. Does it depend on anything?

Not that I'm aware of.

It applies fine on v4.1 or next-20150622.



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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