Re: [PATCH 2/2] PM / Domains: Avoid infinite loops in attach/detach code
From: Rafael J. Wysocki
Date: Mon Jun 22 2015 - 19:15:08 EST
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?
Rafael
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