tracehook: job control

This defines the tracehook_notify_jctl() hook to formalize the ptrace
effects on the job control notifications.  There is no change, only
cleanup.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 10b31ecdd9c8..e9e699f4b1bd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -596,9 +596,6 @@ static int check_kill_permission(int sig, struct siginfo *info,
         return security_task_kill(t, info, sig, 0);
 }
 
-/* forward decl */
-static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
-
 /*
  * Handle magic process-wide effects of stop/continue signals. Unlike
  * the signal actions, these happen immediately at signal-generation
@@ -1605,7 +1602,7 @@ finish_stop(int stop_count)
          * a group stop in progress and we are the last to stop,
          * report to the parent.  When ptraced, every thread reports itself.
          */
-        if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
+        if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(current, CLD_STOPPED);
                 read_unlock(&tasklist_lock);
@@ -1741,6 +1738,9 @@ relock:
                 signal->flags &= ~SIGNAL_CLD_MASK;
                 spin_unlock_irq(&sighand->siglock);
 
+                if (unlikely(!tracehook_notify_jctl(1, why)))
+                        goto relock;
+
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(current->group_leader, why);
                 read_unlock(&tasklist_lock);
@@ -1906,7 +1906,7 @@ void exit_signals(struct task_struct *tsk)
 out:
         spin_unlock_irq(&tsk->sighand->siglock);
 
-        if (unlikely(group_stop)) {
+        if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
                 read_lock(&tasklist_lock);
                 do_notify_parent_cldstop(tsk, CLD_STOPPED);
                 read_unlock(&tasklist_lock);