[PATCH 3/4] signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()

[Oleg Nesterov <oleg@redhat.com>]

Change oom_kill_task() to use do_send_sig_info(SEND_SIG_FORCED)
instead of force_sig(SIGKILL). With the recent changes we do not
need force_ to kill the CLONE_NEWPID tasks.

And this is more correct. force_sig() can race with the exiting
thread even if oom_kill_task() checks p->mm != NULL, while
do_send_sig_info(group => true) kille the whole process.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 mm/oom_kill.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2958fd8..b1e9643 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -472,11 +472,11 @@ static int oom_kill_task(struct task_struct *p)
 			pr_err("Kill process %d (%s) sharing same memory\n",
 				task_pid_nr(q), q->comm);
 			task_unlock(q);
-			force_sig(SIGKILL, q);
+			do_send_sig_info(SIGKILL, SEND_SIG_FORCED, q, true);
 		}
 
 	set_tsk_thread_flag(p, TIF_MEMDIE);
-	force_sig(SIGKILL, p);
+	do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
 
 	return 0;
 }
-- 
1.5.5.1