tracing/boot: Show correct histogram error command

Since trigger_process_regex() modifies given trigger actions
while parsing, the error message couldn't show what command
was passed to the trigger_process_regex() when it returns
an error.

To fix that, show the backed up trigger action command
instead of parsed buffer.

Link: https://lkml.kernel.org/r/162856126413.203126.9465564928450701424.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 1a2b270e9cdac028c95d8f11a46b6aabcc0a8f65..1060b044603213c688b94ab8cc1d0a7d3456a4ba 100644 (file)
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -422,6 +422,7 @@ trace_boot_init_histograms(struct trace_event_file *file,
 {
        struct xbc_node *node;
        const char *p;
+       char *tmp;
 
        xbc_node_for_each_subkey(hnode, node) {
                p = xbc_node_get_data(node);
@@ -429,15 +430,20 @@ trace_boot_init_histograms(struct trace_event_file *file,
                        continue;
                /* All digit started node should be instances. */
                if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
+                       tmp = kstrdup(buf, GFP_KERNEL);
                        if (trigger_process_regex(file, buf) < 0)
-                               pr_err("Failed to apply hist trigger: %s\n", buf);
+                               pr_err("Failed to apply hist trigger: %s\n", tmp);
+                       kfree(tmp);
                }
        }
 
        if (xbc_node_find_child(hnode, "keys")) {
-               if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0)
+               if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
+                       tmp = kstrdup(buf, GFP_KERNEL);
                        if (trigger_process_regex(file, buf) < 0)
-                               pr_err("Failed to apply hist trigger: %s\n", buf);
+                               pr_err("Failed to apply hist trigger: %s\n", tmp);
+                       kfree(tmp);
+               }
        }
 }
 #else
@@ -488,7 +494,7 @@ trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
                        if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
                                pr_err("action string is too long: %s\n", p);
                        else if (trigger_process_regex(file, buf) < 0)
-                               pr_err("Failed to apply an action: %s\n", buf);
+                               pr_err("Failed to apply an action: %s\n", p);
                }
                anode = xbc_node_find_child(enode, "hist");
                if (anode)