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-rw-r--r--kernel/exit.c45
1 files changed, 21 insertions, 24 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 9d6e0897a447..b4d569675d4b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1158,8 +1158,7 @@ static int wait_task_zombie(struct task_struct *p, int noreap,
int __user *stat_addr, struct rusage __user *ru)
{
unsigned long state;
- int retval;
- int status;
+ int retval, status, traced;
if (unlikely(noreap)) {
pid_t pid = p->pid;
@@ -1201,7 +1200,10 @@ static int wait_task_zombie(struct task_struct *p, int noreap,
return 0;
}
- if (likely(p->real_parent == p->parent)) {
+ /* traced means p->ptrace, but not vice versa */
+ traced = (p->real_parent != p->parent);
+
+ if (likely(!traced)) {
struct signal_struct *psig;
struct signal_struct *sig;
@@ -1288,35 +1290,30 @@ static int wait_task_zombie(struct task_struct *p, int noreap,
retval = put_user(p->pid, &infop->si_pid);
if (!retval && infop)
retval = put_user(p->uid, &infop->si_uid);
- if (retval) {
- // TODO: is this safe?
- p->exit_state = EXIT_ZOMBIE;
- return retval;
- }
- retval = p->pid;
- if (p->real_parent != p->parent) {
+ if (!retval)
+ retval = p->pid;
+
+ if (traced) {
write_lock_irq(&tasklist_lock);
- /* Double-check with lock held. */
- if (p->real_parent != p->parent) {
- __ptrace_unlink(p);
- // TODO: is this safe?
- p->exit_state = EXIT_ZOMBIE;
- /*
- * If this is not a detached task, notify the parent.
- * If it's still not detached after that, don't release
- * it now.
- */
+ /* We dropped tasklist, ptracer could die and untrace */
+ ptrace_unlink(p);
+ /*
+ * If this is not a detached task, notify the parent.
+ * If it's still not detached after that, don't release
+ * it now.
+ */
+ if (p->exit_signal != -1) {
+ do_notify_parent(p, p->exit_signal);
if (p->exit_signal != -1) {
- do_notify_parent(p, p->exit_signal);
- if (p->exit_signal != -1)
- p = NULL;
+ p->exit_state = EXIT_ZOMBIE;
+ p = NULL;
}
}
write_unlock_irq(&tasklist_lock);
}
if (p != NULL)
release_task(p);
- BUG_ON(!retval);
+
return retval;
}