1 files changed, 15 insertions, 2 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index d4ccea599692..9c33163a6165 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1961,14 +1961,27 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
                         return;
         }
 
+        set_special_state(TASK_TRACED);
+
         /*
          * We're committing to trapping.  TRACED should be visible before
          * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
          * Also, transition to TRACED and updates to ->jobctl should be
          * atomic with respect to siglock and should be done after the arch
          * hook as siglock is released and regrabbed across it.
+         *
+         *     TRACER                               TRACEE
+         *
+         *     ptrace_attach()
+         * [L]   wait_on_bit(JOBCTL_TRAPPING)   [S] set_special_state(TRACED)
+         *     do_wait()
+         *       set_current_state()                smp_wmb();
+         *       ptrace_do_wait()
+         *         wait_task_stopped()
+         *           task_stopped_code()
+         * [L]         task_is_traced()         [S] task_clear_jobctl_trapping();
          */
-        set_current_state(TASK_TRACED);
+        smp_wmb();
 
         current->last_siginfo = info;
         current->exit_code = exit_code;
@@ -2176,7 +2189,7 @@ static bool do_signal_stop(int signr)
                 if (task_participate_group_stop(current))
                         notify = CLD_STOPPED;
 
-                __set_current_state(TASK_STOPPED);
+                set_special_state(TASK_STOPPED);
                 spin_unlock_irq(&current->sighand->siglock);
 
                 /*