Commit 1ee11844 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

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: default avatarOleg 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 95a3540d
...@@ -60,11 +60,15 @@ static void ptrace_untrace(struct task_struct *child) ...@@ -60,11 +60,15 @@ static void ptrace_untrace(struct task_struct *child)
{ {
spin_lock(&child->sighand->siglock); spin_lock(&child->sighand->siglock);
if (task_is_traced(child)) { 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); __set_task_state(child, TASK_STOPPED);
} else { else
signal_wake_up(child, 1); signal_wake_up(child, 1);
}
} }
spin_unlock(&child->sighand->siglock); spin_unlock(&child->sighand->siglock);
} }
......
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