perf probe: Fix to show correct error string

BugLink: http://bugs.launchpad.net/bugs/890952

commit 44a56040a0037a845d5fa218dffde464579f0cab upstream.

Fix perf probe to show correct error string when it
fails to delete an event. The write(2) returns -1
if failed, and errno stores real error number.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/20111004104504.14591.41266.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index f0223166e76..8c50da86885 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1869,8 +1869,10 @@ static int __del_trace_probe_event(int fd, struct str_node *ent)
 
         pr_debug("Writing event: %s\n", buf);
         ret = write(fd, buf, strlen(buf));
-        if (ret < 0)
+        if (ret < 0) {
+                ret = -errno;
                 goto error;
+        }
 
         printf("Remove event: %s\n", ent->s);
         return 0;