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Subject[PATCH 17/20] job control: Add @for_ptrace to do_notify_parent_cldstop()
Date
Currently, do_notify_parent_cldstop() determines whether the
notification is for the real parent or ptracer. Move the decision to
the caller by adding @for_ptrace parameter to
do_notify_parent_cldstop(). All the callers are updated to pass
task_ptrace(target_task), so this patch doesn't cause any behavior
difference.
While at it, add function comment to do_notify_parent_cldstop().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/signal.c | 31 ++++++++++++++++++++++++-------
1 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 2f2c8f6..69d6054 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1595,16 +1595,30 @@ int do_notify_parent(struct task_struct *tsk, int sig)
return ret;
}

-static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
+/**
+ * do_notify_parent_cldstop - notify parent of stopped/continued state change
+ * @tsk: task reporting the state change
+ * @for_ptracer: the notification is for ptracer
+ * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
+ *
+ * Notify @tsk's parent that the stopped/continued state has changed. If
+ * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
+ * If %true, @tsk reports to @tsk->parent which should be the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with tasklist_lock at least read locked.
+ */
+static void do_notify_parent_cldstop(struct task_struct *tsk,
+ bool for_ptracer, int why)
{
struct siginfo info;
unsigned long flags;
struct task_struct *parent;
struct sighand_struct *sighand;

- if (task_ptrace(tsk))
+ if (for_ptracer) {
parent = tsk->parent;
- else {
+ } else {
tsk = tsk->group_leader;
parent = tsk->real_parent;
}
@@ -1743,7 +1757,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
spin_unlock_irq(&current->sighand->siglock);
read_lock(&tasklist_lock);
if (may_ptrace_stop()) {
- do_notify_parent_cldstop(current, why);
+ do_notify_parent_cldstop(current, task_ptrace(current), why);
/*
* Don't want to allow preemption here, because
* sys_ptrace() needs this task to be inactive.
@@ -1886,7 +1900,8 @@ retry:

if (notify) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, notify);
+ do_notify_parent_cldstop(current, task_ptrace(current),
+ notify);
read_unlock(&tasklist_lock);
}

@@ -1982,6 +1997,7 @@ relock:
* the CLD_ si_code into SIGNAL_CLD_MASK bits.
*/
if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
+ struct task_struct *leader;
int why;

if (signal->flags & SIGNAL_CLD_CONTINUED)
@@ -1994,7 +2010,8 @@ relock:
spin_unlock_irq(&sighand->siglock);

read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current->group_leader, why);
+ leader = current->group_leader;
+ do_notify_parent_cldstop(leader, task_ptrace(leader), why);
read_unlock(&tasklist_lock);
goto relock;
}
@@ -2167,7 +2184,7 @@ out:

if (unlikely(group_stop)) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(tsk, group_stop);
+ do_notify_parent_cldstop(tsk, task_ptrace(tsk), group_stop);
read_unlock(&tasklist_lock);
}
}
--
1.7.1


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