[PATCH 4.4 018/134] perf probe: Return errno when not hitting any event

From: Greg Kroah-Hartman
Date: Mon Mar 19 2018 - 16:32:56 EST


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

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

From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>


[ Upstream commit 70946723eeb859466f026274b29c6196e39149c4 ]

On old perf, when using 'perf probe -d' to delete an inexistent event,
it returns errno, eg,

-bash-4.3# perf probe -d xxx || echo $?
Info: Event "*:xxx" does not exist.
Error: Failed to delete events.
255

But now perf_del_probe_events() will always set ret = 0, different from
previous del_perf_probe_events(). After this, it returns errno again,
eg,

-bash-4.3# ./perf probe -d xxx || echo $?
"xxx" does not hit any event.
Error: Failed to delete events.
254

And it is more appropriate to return -ENOENT instead of -EPERM.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Hanjun Guo <guohanjun@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Fixes: dddc7ee32fa1 ("perf probe: Fix an error when deleting probes successfully")
Link: http://lkml.kernel.org/r/1489738592-61011-1-git-send-email-wangkefeng.wang@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/builtin-probe.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -405,9 +405,9 @@ static int perf_del_probe_events(struct
}

if (ret == -ENOENT && ret2 == -ENOENT)
- pr_debug("\"%s\" does not hit any event.\n", str);
- /* Note that this is silently ignored */
- ret = 0;
+ pr_warning("\"%s\" does not hit any event.\n", str);
+ else
+ ret = 0;

error:
if (kfd >= 0)