blktrace: fix off-by-one bug

'what' is used as the index of array what2act, so it can't >= the array size.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a7f7ff5db38b9f2cfdc469224102248ce2f95ea1..d43cdac7c754f2fe5f1b40d2e7220326d190a45b 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1152,7 +1152,7 @@ static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
        if (!trace_print_context(iter))
                return TRACE_TYPE_PARTIAL_LINE;
 
-       if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
+       if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
                ret = trace_seq_printf(s, "Bad pc action %x\n", what);
        else {
                const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
@@ -1199,7 +1199,7 @@ static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
        t = (const struct blk_io_trace *)iter->ent;
        what = t->action & ((1 << BLK_TC_SHIFT) - 1);
 
-       if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
+       if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
                ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what);
        else {
                const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);