8ef1a6b0d8
Clearing the update_mask bit in fd_insert may lead to duplicate insertion of fd in fd_updt, that could lead to a write past the end of the array. Instead, make sure the update_mask bit is cleared by the pollers no matter what. This should be backported to 1.8. [wt: warning: 1.8 doesn't have the lockless fdcache changes and will require some careful changes in the pollers]