x86, ds: fix bounds check in ds selftest

Fix a bad bounds check in the debug store selftest.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144558.450027000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/kernel/ds_selftest.c b/arch/x86/kernel/ds_selftest.c
index e1ba5101b576..cccc19a38f6d 100644
--- a/arch/x86/kernel/ds_selftest.c
+++ b/arch/x86/kernel/ds_selftest.c
@@ -47,8 +47,13 @@ static int ds_selftest_bts_consistency(const struct bts_trace *trace)
                 printk(KERN_CONT "bad bts buffer setup...");
                 error = -1;
         }
+        /*
+         * We allow top in [begin; end], since its not clear when the
+         * overflow adjustment happens: after the increment or before the
+         * write.
+         */
         if ((trace->ds.top < trace->ds.begin) ||
-            (trace->ds.end <= trace->ds.top)) {
+            (trace->ds.end < trace->ds.top)) {
                 printk(KERN_CONT "bts top out of bounds...");
                 error = -1;
         }