kern/149586: _callout_stop_safe prematurely unsets CALLOUT_ACTIVE
John.Giacomoni at LineRateSystems.com
Thu Aug 12 18:40:04 UTC 2010
>Synopsis: _callout_stop_safe prematurely unsets CALLOUT_ACTIVE
>Arrival-Date: Thu Aug 12 18:40:03 UTC 2010
>Originator: John Giacomoni
_callout_stop_safe(c, 0) prematurely unsets CALLOUT_ACTIVE on inflight callouts making it impossible to know when a callout is actually stopped (one cannot spin on callout_active() to know when it is drained/dead/idle).
This is problematic for unsleepable threads that need to deallocate an object shared with a callout but cannot call callout_drain to guarantee that the reference has been implicitly freed.
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