[PATCH 4.9 269/310] perf tools: Fix copyfile_offset update of output offset

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <jolsa@xxxxxxxxxx>


[ Upstream commit fa1195ccc0af2d121abe0fe266a1caee8c265eea ]

We need to increase output offset in each iteration, not decrease it as
we currently do.

I guess we were lucky to finish in most cases in first iteration, so the
bug never showed. However it shows a lot when working with big (~4GB)
size data.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Fixes: 9c9f5a2f1944 ("perf tools: Introduce copyfile_offset() function")
Link: http://lkml.kernel.org/r/20180109133923.25406-1-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/perf/util/util.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -207,7 +207,7 @@ int copyfile_offset(int ifd, loff_t off_
 
 		size -= ret;
 		off_in += ret;
-		off_out -= ret;
+		off_out += ret;
 	}
 	munmap(ptr, off_in + size);