[RFA/tracepoint] Make GDB can work with some old GDB server

Hui Zhu
2011-06-24T08:47:59Z

Hi,

I got some bug report about ppa in https://lkml.org/lkml/2011/6/4/65
It is:
kgdb_breakpoint () at kernel/kgdb.c:1721
1721 wmb(); /* Sync point after breakpoint */
Sending packet: $qSymbol::#5b...Ack
Packet received:
Packet qSymbol (symbol-lookup) is NOT supported
Sending packet: $qTStatus#49...Ack
Packet received: E22
trace API error 0x2.
(gdb) bt
No stack.
(gdb)

This is because this kgdb(I think trunk have fixed this bug) don't
support qtstatus and reply -0x22.
So gdb throw a error. Then all connect process stop.

This is a bug of kgdb, but I think make gdb just output a warning is
not affect anything else. So I make this patch.

Please help me review it.

Thanks,
Hui

2011-06-24 Hui Zhu <teawater@gmail.com>

* remote.c (remote_start_remote): Add TRY_CATCH for
remote_get_trace_status.
* tracepoint.c (disconnect_tracing): Ditto.
---
remote.c | 13 ++++++++++++-
tracepoint.c | 14 +++++++++++++-
2 files changed, 25 insertions(+), 2 deletions(-)

--- a/remote.c
+++ b/remote.c
@@ -3146,6 +3146,8 @@ remote_start_remote (int from_tty, struc
struct remote_state *rs = get_remote_state ();
struct packet_config *noack_config;
char *wait_status = NULL;
+ int ret = 0;
+ volatile struct gdb_exception ex;

immediate_quit++; /* Allow user to interrupt it. */

@@ -3389,7 +3391,16 @@ remote_start_remote (int from_tty, struc

/* Possibly the target has been engaged in a trace run started
previously; find out where things are at. */
- if (remote_get_trace_status (current_trace_status ()) != -1)
+ TRY_CATCH (ex, RETURN_MASK_ERROR)
+ {
+ ret = remote_get_trace_status (current_trace_status ());
+ }
+ if (ex.reason < 0)
+ {
+ warning(_("%s"), ex.message);
+ ret = -1;
+ }
+ if (ret != -1)
{
struct uploaded_tp *uploaded_tps = NULL;
struct uploaded_tsv *uploaded_tsvs = NULL;
--- a/tracepoint.c
+++ b/tracepoint.c
@@ -1939,11 +1939,23 @@ trace_status_mi (int on_stop)
void
disconnect_tracing (int from_tty)
{
+ int ret = 0;
+ volatile struct gdb_exception ex;
+
/* It can happen that the target that was tracing went away on its
own, and we didn't notice. Get a status update, and if the
current target doesn't even do tracing, then assume it's not
running anymore. */
- if (target_get_trace_status (current_trace_status ()) < 0)
+ TRY_CATCH (ex, RETURN_MASK_ERROR)
+ {
+ ret = target_get_trace_status (current_trace_status ());
+ }
+ if (ex.reason < 0)
+ {
+ warning(_("%s"), ex.message);
+ ret = -1;
+ }
+ if (ret < 0)
current_trace_status ()->running = 0;

/* If running interactively, give the user the option to cancel and