change next_thread() to use __next_thread() ?: group_leader

This relies on fact that group leader is always the 1st entry in the
signal->thread_head list.

With or without this change, if the lockless next_thread(last_thread)
races with exec it can return the old or the new leader.

We are almost ready to kill task->thread_group, after this change its
only user is thread_group_empty().

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions