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[PATCH] infcmd, btrace: fix crash in 'finish' for tailcall-only frames
- From: Markus Metzger <markus dot t dot metzger at intel dot com>
- To: gdb-patches at sourceware dot org
- Cc: yao dot qi at arm dot com
- Date: Tue, 31 May 2016 09:36:05 +0200
- Subject: [PATCH] infcmd, btrace: fix crash in 'finish' for tailcall-only frames
- Authentication-results: sourceware.org; auth=none
Patch 7eb895307f53 Skip unwritable frames in command "finish"
skips non-writable frames in addition to tailcall frames.
If skip_tailcall_frames already returns NULL, skip_unwritable_frames
will be called with a NULL frame and crash in get_frame_arch. This is
caught by gdb.btrace/tailcall-only.exp.
Further, if we ever end up with a mixture of tailcall and non-writable
frames, we may not skip all of them, as intended.
Loop over skip_tailcall_frames and skip_unwritable_frames as long as at least
one of them makes progress.
2016-05-31 Markus Metzger <markus.t.metzger@intel.com>
* infcmd.c (skip_finish_frames): New.
(finish_command): Call skip_finish_frames.
---
gdb/infcmd.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 14d51fd..ca8655a 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1927,6 +1927,28 @@ finish_forward (struct finish_command_fsm *sm, struct frame_info *frame)
proceed ((CORE_ADDR) -1, GDB_SIGNAL_DEFAULT);
}
+/* Skip frames for "finish". */
+
+static struct frame_info *
+skip_finish_frames (struct frame_info *frame)
+{
+ struct frame_info *start;
+
+ do {
+ start = frame;
+
+ frame = skip_tailcall_frames (frame);
+ if (frame == NULL)
+ break;
+
+ frame = skip_unwritable_frames (frame);
+ if (frame == NULL)
+ break;
+ } while (start != frame);
+
+ return frame;
+}
+
/* "finish": Set a temporary breakpoint at the place the selected
frame will return to, then continue. */
@@ -2025,11 +2047,7 @@ finish_command (char *arg, int from_tty)
finish_backward (sm);
else
{
- /* Ignore TAILCALL_FRAME type frames, they were executed already before
- entering THISFRAME. */
- frame = skip_tailcall_frames (frame);
-
- frame = skip_unwritable_frames (frame);
+ frame = skip_finish_frames (frame);
if (frame == NULL)
error (_("Cannot find the caller frame."));
--
1.8.3.1