signals: do_tkill: don't use tasklist_lock
Convert do_tkill() to use rcu_read_lock() + lock_task_sighand() to avoid
taking tasklist lock.
Note that we don't return an error if lock_task_sighand() fails, we pretend
the task dies after receiving the signal. Otherwise, we should fight with the
nasty races with mt-exec without having any advantage.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed