1 files changed, 5 insertions, 2 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 2dc00298e678..fdb34e86f923 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -99,9 +99,12 @@ int ptrace_check_attach(struct task_struct *child, int kill)
          * be changed by us so it's not changing right after this.
          */
         read_lock(&tasklist_lock);
-        if ((child->ptrace & PT_PTRACED) && child->parent == current &&
-             child->signal != NULL) {
+        if ((child->ptrace & PT_PTRACED) && child->parent == current) {
                 ret = 0;
+                /*
+                 * child->sighand can't be NULL, release_task()
+                 * does ptrace_unlink() before __exit_signal().
+                 */
                 spin_lock_irq(&child->sighand->siglock);
                 if (task_is_stopped(child))
                         child->state = TASK_TRACED;