commit b8abd0f49d680c9f943ac460a5eba291424bb6d0
Author: Michael Petlan <mpetlan@redhat.com>
Date:   Tue Dec 12 03:43:11 2017 +0100

    perf trace: support multiple -e arguments
    
    Other perf subcommands, such as perf-stat allow multiple event specification
    arguments, like "perf stat -e evt1 -e evt2 ...".
    
    This patch enables perf-trace to allow that too.
    
    Before:
         0.030 ( 0.004 ms): true/19173 close(fd: 3) = 0
         0.089 ( 0.007 ms): true/19173 close(fd: 3) = 0
    
    After:
         0.018 ( 0.013 ms): true/19175 open(filename: /etc/ld.so.cache, flags: CLOEXEC) = 3
         0.040 ( 0.004 ms): true/19175 close(fd: 3</etc/ld.so.cache>) = 0
         0.053 ( 0.014 ms): true/19175 open(filename: /lib64/libc.so.6, flags: CLOEXEC) = 3
         0.107 ( 0.006 ms): true/19175 close(fd: 3</lib64/libc.so.6>) = 0
    
    Signed-off-by: Michael Petlan <mpetlan@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 7c57898..abcfdcc 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2935,10 +2935,18 @@ static int trace__parse_events_option(const struct option *opt, const char *str,
 			.dirname = strace_groups_dir,
 		};
 
-		trace->ev_qualifier = strlist__new(lists[1], &slist_config);
 		if (trace->ev_qualifier == NULL) {
-			fputs("Not enough memory to parse event qualifier", trace->output);
-			goto out;
+			trace->ev_qualifier = strlist__new(lists[1], &slist_config);
+			if (trace->ev_qualifier == NULL) {
+				fputs("Not enough memory to parse event qualifier", trace->output);
+				goto out;
+			}
+		} else {
+			int rv = strlist__add(trace->ev_qualifier, lists[1]);
+			if (rv != 0) {
+				fputs("A problem occurred when parsing event qualifier", trace->output);
+				goto out;
+			}
 		}
 
 		if (trace__validate_ev_qualifier(trace))