[S390] duplicate SIGTRAP on signal delivery.

The code in do_signal sets the TIF_SINGLE_STEP bit and calls
tracehook_signal_handler after the signal frame has been set up.
This causes two SIGTRAP signals to be delivered to the tracer.
Stop setting the TIF_SINGLE_STEP bit in do_signal to get the
correct number of SIGTRAPs.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 6b4fef8..1675c48 100644 (file)
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -500,18 +500,10 @@ void do_signal(struct pt_regs *regs)
                                clear_thread_flag(TIF_RESTORE_SIGMASK);
 
                        /*
-                        * If we would have taken a single-step trap
-                        * for a normal instruction, act like we took
-                        * one for the handler setup.
-                        */
-                       if (current->thread.per_info.single_step)
-                               set_thread_flag(TIF_SINGLE_STEP);
-
-                       /*
                         * Let tracing know that we've done the handler setup.
                         */
                        tracehook_signal_handler(signr, &info, &ka, regs,
-                                        test_thread_flag(TIF_SINGLE_STEP));
+                                       current->thread.per_info.single_step);
                }
                return;
        }