freezer: use lock_task_sighand() in fake_signal_wake_up()

cgroup_freezer calls freeze_task() without holding tasklist_lock and,
if the task is exiting, its ->sighand may be gone by the time
fake_signal_wake_up() is called.  Use lock_task_sighand() instead of
accessing ->sighand directly.

Signed-off-by: Tejun Heo <[email protected]>
Reported-by: Oleg Nesterov <[email protected]>
Acked-by: Oleg Nesterov <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Paul Menage <[email protected]>

0 files changed, 0 insertions, 0 deletions