gdbserver/Linux: unbreak non-stop

The previous change added an assertion that is catching yet another
bug in count_events_callback/select_event_lwp_callback:

  (gdb)
  PASS: gdb.mi/mi-nonstop.exp: interrupted
  mi_expect_interrupt: expecting: \*stopped,(reason="signal-received",signal-name="0",signal-meaning="Signal 0"|reason="signal-received",signal-name="SIGINT",signal-meaning="Interrupt")[^
  ]*

  /home/pedro/gdb/mygit/src/gdb/gdbserver/linux-low.c:2329: A problem internal to GDBserver has been detected.
  select_event_lwp: Assertion `num_events > 0' failed.
  =thread-group-exited,id="i1"

Certainly select_event_lwp_callback should always at least find one
event, as it's only called because an event triggered (though we may
have more than one: the point of the function is randomly picking
one).

An LWP that GDB previously asked to continue/step (thus is resumed)
and gets a vCont;t request ends up with last_resume_kind ==
resume_stop.  These functions in gdbserver used to filter out events
that weren't going to be reported to GDB; I think the last_resume_kind
kind check used to make sense at that point, but it no longer does.

gdb/gdbserver/ChangeLog:
2015-03-19  Pedro Alves  <palves@redhat.com>

	* linux-low.c (count_events_callback, select_event_lwp_callback):
	No longer check whether the thread has resume_stop as last resume
	kind.

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index df8f9ab888c820bae2f2958291238654126295d1..0383e67c59a3f1646bca74b3dfdc34fa5482bbed 100644 (file)
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-19  Pedro Alves  <palves@redhat.com>
+
+       * linux-low.c (count_events_callback, select_event_lwp_callback):
+       No longer check whether the thread has resume_stop as last resume
+       kind.
+
 2015-03-19 Pedro Alves  <palves@redhat.com>
 
        * linux-low.c (count_events_callback, select_event_lwp_callback):

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index e53e0fc187d39cf5996e6c6e16de01485721f778..2b988ec13611c0154bc575c16ab5f1bf4dcef04c 100644 (file)
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -2245,7 +2245,6 @@ count_events_callback (struct inferior_list_entry *entry, void *data)
 
   /* Count only resumed LWPs that have an event pending. */
   if (thread->last_status.kind == TARGET_WAITKIND_IGNORE
-      && thread->last_resume_kind != resume_stop
       && lp->status_pending_p)
     (*count)++;
 
@@ -2280,8 +2279,7 @@ select_event_lwp_callback (struct inferior_list_entry *entry, void *data)
   gdb_assert (selector != NULL);
 
   /* Select only resumed LWPs that have an event pending. */
-  if (thread->last_resume_kind != resume_stop
-      && thread->last_status.kind == TARGET_WAITKIND_IGNORE
+  if (thread->last_status.kind == TARGET_WAITKIND_IGNORE
       && lp->status_pending_p)
     if ((*selector)-- == 0)
       return 1;