[34-longterm 046/196] repair gdbstub to match the gdbserial protocol specification

[Paul Gortmaker]

From: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit fb82c0ff27b2c40c6f7a3d1a94cafb154591fa80 upstream.

The gdbserial protocol handler should return an empty packet instead
of an error string when ever it responds to a command it does not
implement.

The problem cases come from a debugger client sending
qTBuffer, qTStatus, qSearch, qSupported.

The incorrect response from the gdbstub leads the debugger clients to
not function correctly.  Recent versions of gdb will not detach correctly as a result of this behavior.

[PG: file renamed by time of fb82c0ff  kgdb.c --> debug/gdbstub.c]

Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 kernel/kgdb.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 11f3515..0887213 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -976,10 +976,8 @@ static void gdb_cmd_query(struct kgdb_state *ks)
 	switch (remcom_in_buffer[1]) {
 	case 's':
 	case 'f':
-		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
-			error_packet(remcom_out_buffer, -EINVAL);
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
 			break;
-		}
 
 		i = 0;
 		remcom_out_buffer[0] = 'm';
@@ -1020,10 +1018,9 @@ static void gdb_cmd_query(struct kgdb_state *ks)
 		pack_threadid(remcom_out_buffer + 2, thref);
 		break;
 	case 'T':
-		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
-			error_packet(remcom_out_buffer, -EINVAL);
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
 			break;
-		}
+
 		ks->threadid = 0;
 		ptr = remcom_in_buffer + 17;
 		kgdb_hex2long(&ptr, &ks->threadid);
-- 
1.7.9.3

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