send_sig is thread only making it the wrong command for an action
         directed at a process.

force_sig does not set SEND_SIG_FORCED (causing unnecessary work in
         __send_signal) and jumps through unnecessary hoops to deal
         with blocked and ignored signals which SIGKILL can never be.

Therefore use do_send_sig_info in all cases in __do_SAK to kill
tasks as allows for exactly what the code wants to do.

Signed-off-by: "Eric W. Biederman" <ebied...@xmission.com>
---
 drivers/tty/tty_io.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index cec58c53b0c4..42ac168c2a47 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2747,7 +2747,7 @@ void __do_SAK(struct tty_struct *tty)
        do_each_pid_task(session, PIDTYPE_SID, p) {
                tty_notice(tty, "SAK: killed process %d (%s): by session\n",
                           task_pid_nr(p), p->comm);
-               send_sig(SIGKILL, p, 1);
+               do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
        } while_each_pid_task(session, PIDTYPE_SID, p);
 
        /* Now kill any processes that happen to have the tty open */
@@ -2755,7 +2755,7 @@ void __do_SAK(struct tty_struct *tty)
                if (p->signal->tty == tty) {
                        tty_notice(tty, "SAK: killed process %d (%s): by 
controlling tty\n",
                                   task_pid_nr(p), p->comm);
-                       send_sig(SIGKILL, p, 1);
+                       do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
                        continue;
                }
                task_lock(p);
@@ -2763,7 +2763,7 @@ void __do_SAK(struct tty_struct *tty)
                if (i != 0) {
                        tty_notice(tty, "SAK: killed process %d (%s): by 
fd#%d\n",
                                   task_pid_nr(p), p->comm, i - 1);
-                       force_sig(SIGKILL, p);
+                       do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
                }
                task_unlock(p);
        } while_each_thread(g, p);
-- 
2.17.1

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