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-rw-r--r--include/linux/sched.h6
-rw-r--r--kernel/signal.c62
2 files changed, 60 insertions, 8 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4b601be3dace..85f51042c2b8 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1260,6 +1260,7 @@ struct task_struct {
int exit_state;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
+ unsigned int group_stop; /* GROUP_STOP_*, siglock protected */
/* ??? */
unsigned int personality;
unsigned did_exec:1;
@@ -1771,6 +1772,11 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
#define used_math() tsk_used_math(current)
+/*
+ * task->group_stop flags
+ */
+#define GROUP_STOP_CONSUME (1 << 17) /* consume group stop count */
+
#ifdef CONFIG_PREEMPT_RCU
#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
diff --git a/kernel/signal.c b/kernel/signal.c
index 95ac42dc3bcb..ecb20089eaff 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -223,6 +223,52 @@ static inline void print_dropped_signal(int sig)
current->comm, current->pid, sig);
}
+/**
+ * task_clear_group_stop_pending - clear pending group stop
+ * @task: target task
+ *
+ * Clear group stop states for @task.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static void task_clear_group_stop_pending(struct task_struct *task)
+{
+ task->group_stop &= ~GROUP_STOP_CONSUME;
+}
+
+/**
+ * task_participate_group_stop - participate in a group stop
+ * @task: task participating in a group stop
+ *
+ * @task is participating in a group stop. Group stop states are cleared
+ * and the group stop count is consumed if %GROUP_STOP_CONSUME was set. If
+ * the consumption completes the group stop, the appropriate %SIGNAL_*
+ * flags are set.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static bool task_participate_group_stop(struct task_struct *task)
+{
+ struct signal_struct *sig = task->signal;
+ bool consume = task->group_stop & GROUP_STOP_CONSUME;
+
+ task_clear_group_stop_pending(task);
+
+ if (!consume)
+ return false;
+
+ if (!WARN_ON_ONCE(sig->group_stop_count == 0))
+ sig->group_stop_count--;
+
+ if (!sig->group_stop_count) {
+ sig->flags = SIGNAL_STOP_STOPPED;
+ return true;
+ }
+ return false;
+}
+
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
@@ -1645,7 +1691,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
* we must participate in the bookkeeping.
*/
if (current->signal->group_stop_count > 0)
- --current->signal->group_stop_count;
+ task_participate_group_stop(current);
current->last_siginfo = info;
current->exit_code = exit_code;
@@ -1730,6 +1776,7 @@ static int do_signal_stop(int signr)
int notify = 0;
if (!sig->group_stop_count) {
+ unsigned int gstop = GROUP_STOP_CONSUME;
struct task_struct *t;
if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
@@ -1741,6 +1788,7 @@ static int do_signal_stop(int signr)
*/
sig->group_exit_code = signr;
+ current->group_stop = gstop;
sig->group_stop_count = 1;
for (t = next_thread(current); t != current; t = next_thread(t))
/*
@@ -1750,19 +1798,19 @@ static int do_signal_stop(int signr)
*/
if (!(t->flags & PF_EXITING) &&
!task_is_stopped_or_traced(t)) {
+ t->group_stop = gstop;
sig->group_stop_count++;
signal_wake_up(t, 0);
- }
+ } else
+ task_clear_group_stop_pending(t);
}
/*
* If there are no other threads in the group, or if there is
* a group stop in progress and we are the last to stop, report
* to the parent. When ptraced, every thread reports itself.
*/
- if (!--sig->group_stop_count) {
- sig->flags = SIGNAL_STOP_STOPPED;
+ if (task_participate_group_stop(current))
notify = CLD_STOPPED;
- }
if (task_ptrace(current))
notify = CLD_STOPPED;
@@ -2026,10 +2074,8 @@ void exit_signals(struct task_struct *tsk)
recalc_sigpending_and_wake(t);
if (unlikely(tsk->signal->group_stop_count) &&
- !--tsk->signal->group_stop_count) {
- tsk->signal->flags = SIGNAL_STOP_STOPPED;
+ task_participate_group_stop(tsk))
group_stop = CLD_STOPPED;
- }
out:
spin_unlock_irq(&tsk->sighand->siglock);