Hi. On Tuesday 19 June 2007 07:29:58 Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <[email protected]> > > At present, if a user mode helper is running while usermodehelper_pm_callback() > is executed, the helper may be frozen and the completion in > call_usermodehelper_exec() won't be completed until user space processes are > thawed. As a result, the freezing of kernel threads may fail, which is not > desirable. > > Prevent this from happening by introducing a counter of running user mode > helpers and allowing usermodehelper_pm_callback() to succeed for > action = PM_HIBERNATION_PREPARE or action = PM_SUSPEND_PREPARE only if there > are no helpers running. [Namely, usermodehelper_pm_callback() waits for at most > RUNNING_HELPERS_TIMEOUT for the number of running helpers to become zero and > fails if that doesn't happen.] > > Special thanks to Uli Luckas <[email protected]> for reviewing the previous > versions of this patch and for very useful comments. > > Signed-off-by: Rafael J. Wysocki <[email protected]> Acked-by: Nigel Cunningham <[email protected]> Regards, Nigel
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- From: "Rafael J. Wysocki" <[email protected]>
- [RFC][PATCH -mm] PM: Prevent frozen user mode helpers from failing the freezing of tasks
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