[PATCH 4/4] utrace_do_stop: s/STOPPED/TRACED/ to protect against SIGCONT

[Oleg Nesterov]

utrace_do_stop() sets utrace->stopped but leaves the tracee in TASK_STOPPED
state. This means SIGCONT can wake up the tracee and fool the tracer.

Signed-off-by: Oleg Nesterov <o...@redhat.com>
---

 kernel/utrace.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- __UTRACE/kernel/utrace.c~JCTL_4_STOP_TRACED 2009-07-28 23:59:28.000000000 
+0200
+++ __UTRACE/kernel/utrace.c    2009-07-29 00:14:42.000000000 +0200
@@ -788,8 +788,9 @@ static bool utrace_do_stop(struct task_s
        } else if (task_is_stopped(target)) {
                /*
                 * Stopped is considered quiescent; when it wakes up, it will
-                * go through utrace_get_signal() before doing anything else.
+                * go through utrace_finish_jctl() before doing anything else.
                 */
+               __set_task_state(target, TASK_TRACED);
                utrace->stopped = stopped = true;
        } else if (!utrace->report && !utrace->interrupt) {
                utrace->report = 1;