More robust fix of signal-before-singlestep problem
- On s390x, when we PTRACE_CONT the process, it will actually continue,
even though we ordered PTRACE_SINGLESTEP before. So always issue
PTRACE_SINGLESTEP when we get signal before singlestep.
- Also, simply queue the signal as usual.
diff --git a/sysdeps/linux-gnu/trace.c b/sysdeps/linux-gnu/trace.c
index 1a82b41..5337cb0 100644
--- a/sysdeps/linux-gnu/trace.c
+++ b/sysdeps/linux-gnu/trace.c
@@ -556,6 +556,14 @@
return 1;
}
+static void
+singlestep(Process * proc)
+{
+ debug(1, "PTRACE_SINGLESTEP");
+ if (ptrace(PTRACE_SINGLESTEP, proc->pid, 0, 0))
+ perror("PTRACE_SINGLESTEP");
+}
+
/* This event handler is installed when we are in the process of
* stopping the whole thread group to do the pointer re-enablement for
* one of the threads. We pump all events to the queue for later
@@ -595,24 +603,19 @@
teb->pid);
if (sbp->enabled)
disable_breakpoint(teb, sbp);
- if (ptrace(PTRACE_SINGLESTEP, teb->pid, 0, 0))
- perror("PTRACE_SINGLESTEP");
+ singlestep(teb);
self->state = state = psh_singlestep;
}
break;
- case psh_singlestep: {
+ case psh_singlestep:
/* In singlestep state, breakpoint signifies that we
* have now stepped, and can re-enable the breakpoint. */
if (event != NULL && task == teb) {
- /* Let the outer shell handle this event and
- * continue the process. The breakpoint
- * should arrive afterwards. */
+ /* This is not the singlestep that we are waiting for. */
if (event->type == EVENT_SIGNAL) {
- debug(DEBUG_PROCESS,
- "SIGNAL after SINGLESTEP %d", teb->pid);
- event_to_queue = 0;
+ singlestep(task);
break;
}
@@ -631,7 +634,6 @@
event = NULL; // handled
} else
break;
- }
/* fall-through */