threadgroup_lock — lock threadgroup
void threadgroup_lock ( | struct task_struct * tsk); |
Lock the threadgroup tsk belongs to. No new task is allowed to enter
and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
change ->group_leader/pid. This is useful for cases where the threadgroup
needs to stay stable across blockable operations.
fork and exit paths explicitly call threadgroup_change_{begin|end}() for synchronization. While held, no new task will be added to threadgroup and no existing live task will have its PF_EXITING set.
de_thread does threadgroup_change_{begin|end}() when a non-leader
sub-thread becomes a new leader.