Callouts and Race Conditions
Because callout functions execute asynchronously, it’s possible for a callout function to be called while another thread attempts to stop or reschedule it; thus creating a race condition. Fortunately, there are two simple solutions available for solving this problem:
- Use
callout_init_mtx
,callout_init_rw
, orcallout_init(foo, 0)
Callout functions associated with a lock are exempt from the race condition described above—as long as the associated lock is held before calling the callout management functions.
- Use
callout_drain
to permanently cancel a callout function Use
callout_drain
instead ofcallout_stop
to permanently cancel a callout function. See, by waiting for the callout function to finish, you can’t destroy any ...
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