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-rw-r--r--kernel/exit.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 5cbc83e..3383793 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1377,11 +1377,23 @@ static int *task_stopped_code(struct task_struct *p, bool ptrace)
return NULL;
}
-/*
- * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
- * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
- * the lock and this task is uninteresting. If we return nonzero, we have
- * released the lock and the system call should return.
+/**
+ * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
+ * @wo: wait options
+ * @ptrace: is the wait for ptrace
+ * @p: task to wait for
+ *
+ * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
+ *
+ * CONTEXT:
+ * read_lock(&tasklist_lock), which is released if return value is
+ * non-zero. Also, grabs and releases @p->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 if wait condition didn't exist and search for other wait conditions
+ * should continue. Non-zero return, -errno on failure and @p's pid on
+ * success, implies that tasklist_lock is released and wait condition
+ * search should terminate.
*/
static int wait_task_stopped(struct wait_opts *wo,
int ptrace, struct task_struct *p)
@@ -1397,6 +1409,9 @@ static int wait_task_stopped(struct wait_opts *wo,
if (!ptrace && !(wo->wo_flags & WUNTRACED))
return 0;
+ if (!task_stopped_code(p, ptrace))
+ return 0;
+
exit_code = 0;
spin_lock_irq(&p->sighand->siglock);
@@ -1607,8 +1622,9 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
* Wait for stopped. Depending on @ptrace, different stopped state
* is used and the two don't interact with each other.
*/
- if (task_stopped_code(p, ptrace))
- return wait_task_stopped(wo, ptrace, p);
+ ret = wait_task_stopped(wo, ptrace, p);
+ if (ret)
+ return ret;
/*
* Wait for continued. There's only one continued state and the
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