debug_core,kdb: fix crash when arch does not have single step

When an arch such as mips and microblaze does not implement either HW
or software single stepping the debug core should re-enter kdb.  The
kdb code will properly ignore the single step operation.  Attempting
to single step the kernel without software or hardware support causes
unpredictable kernel crashes.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 8bc5eeffec8a953f844d853cc9abe30bbb4d77c4..9ed9307615d9ab0c6132333756f9c44bc56a4bde 100644 (file)
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -605,6 +605,8 @@ cpu_master_loop:
                if (dbg_kdb_mode) {
                        kgdb_connected = 1;
                        error = kdb_stub(ks);
+                       if (error == -1)
+                               continue;
                        kgdb_connected = 0;
                } else {
                        error = gdb_serial_stub(ks);