On Mon, Dec 21, 2015 at 04:35:23PM +0200, Saeed Mahameed wrote:

think of a case where:
CPU1: is just about to call
"schedule_delayed_work(&tstamp->overflow_work,
tstamp->overflow_period);"
CPU2: cancel_delayed_work

In this case cancel_dalyed_work_sync (CPU2) will wait for CPU1 to
complete but CPU1 will re-arm the work, and we will
be left with tstamp->overflow_work running forever.

This is my understanding:  Once the work becomes re-queued, it will be
canceled before running again.

Thanks,
Richard