ptrace_untrace: fix the SIGNAL_STOP_STOPPED check
This bug is ancient too. ptrace_untrace() must not resume the task
if the group stop in progress, we should set TASK_STOPPED instead.
Unfortunately, we still have problems here:
- if the process/thread was traced, SIGNAL_STOP_STOPPED
does not necessary means this thread group is stopped.
- ptrace breaks the bookkeeping of ->group_stop_count.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 296e810..5105f5a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -60,11 +60,15 @@
{
spin_lock(&child->sighand->siglock);
if (task_is_traced(child)) {
- if (child->signal->flags & SIGNAL_STOP_STOPPED) {
+ /*
+ * If the group stop is completed or in progress,
+ * this thread was already counted as stopped.
+ */
+ if (child->signal->flags & SIGNAL_STOP_STOPPED ||
+ child->signal->group_stop_count)
__set_task_state(child, TASK_STOPPED);
- } else {
+ else
signal_wake_up(child, 1);
- }
}
spin_unlock(&child->sighand->siglock);
}
