From 1ee1184485df9c9a3503d3a684b911fb7c73d259 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 2 Apr 2009 16:58:23 -0700 Subject: [PATCH] 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 Cc: Jerome Marchand Cc: Roland McGrath Cc: Denys Vlasenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/ptrace.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) 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 @@ static void ptrace_untrace(struct task_struct *child) { 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); } -- 1.8.2.3