diff --git a/strbuf.c b/strbuf.c
index cccfdec0e3..c986ec28f4 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -134,6 +134,13 @@ void strbuf_trim_trailing_dir_sep(struct strbuf *sb)
 	sb->buf[sb->len] = '\0';
 }
 
+void strbuf_trim_trailing_ch(struct strbuf *sb, int c)
+{
+	while (sb->len > 0 && sb->buf[sb->len - 1] == c)
+		sb->len--;
+	sb->buf[sb->len] = '\0';
+}
+
 void strbuf_trim_trailing_newline(struct strbuf *sb)
 {
 	if (sb->len > 0 && sb->buf[sb->len - 1] == '\n') {
diff --git a/strbuf.h b/strbuf.h
index 884157873e..5e389ab065 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -197,6 +197,9 @@ void strbuf_trim_trailing_dir_sep(struct strbuf *sb);
 /* Strip trailing LF or CR/LF */
 void strbuf_trim_trailing_newline(struct strbuf *sb);
 
+/* Strip trailing character c */
+void strbuf_trim_trailing_ch(struct strbuf *sb, int c);
+
 /**
  * Replace the contents of the strbuf with a reencoded form.  Returns -1
  * on error, 0 on success.
diff --git a/trace2/tr2_cfg.c b/trace2/tr2_cfg.c
index d96d908bb9..356fcd38f4 100644
--- a/trace2/tr2_cfg.c
+++ b/trace2/tr2_cfg.c
@@ -33,10 +33,7 @@ static int tr2_cfg_load_patterns(void)
 
 	tr2_cfg_patterns = strbuf_split_buf(envvar, strlen(envvar), ',', -1);
 	for (s = tr2_cfg_patterns; *s; s++) {
-		struct strbuf *buf = *s;
-
-		if (buf->len && buf->buf[buf->len - 1] == ',')
-			strbuf_setlen(buf, buf->len - 1);
+		strbuf_trim_trailing_ch(*s, ',');
 		strbuf_trim_trailing_newline(*s);
 		strbuf_trim(*s);
 	}
@@ -72,10 +69,7 @@ static int tr2_load_env_vars(void)
 
 	tr2_cfg_env_vars = strbuf_split_buf(varlist, strlen(varlist), ',', -1);
 	for (s = tr2_cfg_env_vars; *s; s++) {
-		struct strbuf *buf = *s;
-
-		if (buf->len && buf->buf[buf->len - 1] == ',')
-			strbuf_setlen(buf, buf->len - 1);
+		strbuf_trim_trailing_ch(*s, ',');
 		strbuf_trim_trailing_newline(*s);
 		strbuf_trim(*s);
 	}