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

From "Rafael J. Wysocki" <rjw@rjwysocki.net>
Newsgroups linux.kernel
Subject Re: [PATCH 2/2] PM / Domains: Avoid infinite loops in attach/detach code
Date 2015-06-23 01:20 +0200
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References <pCFf4-5FO-15@gated-at.bofh.it> <pE4uJ-5vJ-7@gated-at.bofh.it>
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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@glider.be>

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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Re: [PATCH 2/2] PM / Domains: Avoid infinite loops in attach/detach code "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-06-23 01:20 +0200

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