Hi.

On Tuesday 19 June 2007 07:29:58 Rafael J. Wysocki wrote:
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> From: Rafael J. Wysocki <rjw@sisk.pl>
>=20
> At present, if a user mode helper is running while=20
usermodehelper_pm_callback()
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> is executed, the helper may be frozen and the completion in
> call_usermodehelper_exec() won't be completed until user space processes =
are
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> thawed.  As a result, the freezing of kernel threads may fail, which is n=
ot
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> desirable.
>=20
> Prevent this from happening by introducing a counter of running user mode
> helpers and allowing usermodehelper_pm_callback() to succeed for
> action =3D PM_HIBERNATION_PREPARE or action =3D PM_SUSPEND_PREPARE only i=
f there
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> are no helpers running.  [Namely, usermodehelper_pm_callback() waits for =
at=20
most
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> RUNNING_HELPERS_TIMEOUT for the number of running helpers to become zero =
and
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> fails if that doesn't happen.]
>=20
> Special thanks to Uli Luckas <u.luckas@road.de> for reviewing the previous
> versions of this patch and for very useful comments.
>=20
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>

Regards,

Nigel