[tip:tracing/blktrace] blktrace: fix off-by-one bug

[Li Zefan]

Commit-ID:  89b0d8901c251548ee4d835da184dd08af67a3a7
Gitweb:     http://git.kernel.org/tip/89b0d8901c251548ee4d835da184dd08af67a3a7
Author:     Li Zefan <lizf@xxxxxxxxxxxxxx>
AuthorDate: Tue, 24 Mar 2009 16:05:27 +0800
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 25 Mar 2009 14:13:11 +0100

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@xxxxxxxxxxxxxx>
Acked-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Acked-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
LKML-Reference: <49C89447.5060303@xxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
 kernel/trace/blktrace.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a7f7ff5..d43cdac 100644
--- 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);
--
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