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authorOleg Nesterov <oleg@redhat.com>2011-06-22 23:08:53 +0200
committerOleg Nesterov <oleg@redhat.com>2011-06-27 20:30:08 +0200
commit9843a1e977977986d0a4c1000f2229b032572534 (patch)
tree8c3d8a77ed8b2a021451a493aa47162977c8001b /kernel/ptrace.c
parent45cdf5cc0703c537194588c63d53bad1f2539d36 (diff)
__ptrace_detach: avoid task_detached(), check do_notify_parent()
__ptrace_detach() relies on the current obscure behaviour of do_notify_parent(tsk) which changes tsk->exit_signal if this child should be silently reaped. That is why we check task_detached(), it is true if the task is sub-thread, or it is the group_leader but its exit_signal was changed by do_notify_parent(). This is confusing, change the code to rely on !thread_group_leader() or the value returned by do_notify_parent(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r--kernel/ptrace.c33
1 files changed, 18 insertions, 15 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index e18966c1c0da..66a28bd71ef6 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -370,25 +370,28 @@ static int ignoring_children(struct sighand_struct *sigh)
*/
static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
{
+ bool dead;
+
__ptrace_unlink(p);
- if (p->exit_state == EXIT_ZOMBIE) {
- if (!task_detached(p) && thread_group_empty(p)) {
- if (!same_thread_group(p->real_parent, tracer))
- do_notify_parent(p, p->exit_signal);
- else if (ignoring_children(tracer->sighand)) {
- __wake_up_parent(p, tracer);
- p->exit_signal = -1;
- }
- }
- if (task_detached(p)) {
- /* Mark it as in the process of being reaped. */
- p->exit_state = EXIT_DEAD;
- return true;
+ if (p->exit_state != EXIT_ZOMBIE)
+ return false;
+
+ dead = !thread_group_leader(p);
+
+ if (!dead && thread_group_empty(p)) {
+ if (!same_thread_group(p->real_parent, tracer))
+ dead = do_notify_parent(p, p->exit_signal);
+ else if (ignoring_children(tracer->sighand)) {
+ __wake_up_parent(p, tracer);
+ p->exit_signal = -1;
+ dead = true;
}
}
-
- return false;
+ /* Mark it as in the process of being reaped. */
+ if (dead)
+ p->exit_state = EXIT_DEAD;
+ return dead;
}
static int ptrace_detach(struct task_struct *child, unsigned int data)