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authorOleg Nesterov <oleg@redhat.com>2009-04-02 16:58:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 19:05:00 -0700
commit1ee1184485df9c9a3503d3a684b911fb7c73d259 (patch)
tree0216bc3ebccf1c44b86617cd06e7b93510ef5bb8
parent95a3540da9c81a5987be810e1d9a83640a366bd5 (diff)
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>
-rw-r--r--kernel/ptrace.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 296e8105863a..5105f5a6a2ce 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);
}