tracing: Fix wrong usage of strstrip in trace_ksyms

strstrip returns a pointer to the first non space character, but the
code in parse_ksym_trace_str() ignores that.

strstrip is now must_check and therefor we get the correct warning:
kernel/trace/trace_ksym.c:294: warning:
ignoring return value of ‘strstrip’, declared with attribute warn_unused_result

We are really not interested in leading whitespace here.

Fix that and cleanup the dozen kfree() exit pathes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 21 insertions, 28 deletions

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index ddfa0fd43bc0..64e7a5bd6692 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -277,21 +277,20 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 {
         struct trace_ksym *entry;
         struct hlist_node *node;
-        char *input_string, *ksymname = NULL;
+        char *buf, *input_string, *ksymname = NULL;
         unsigned long ksym_addr = 0;
         int ret, op, changed = 0;
 
-        input_string = kzalloc(count + 1, GFP_KERNEL);
-        if (!input_string)
+        buf = kzalloc(count + 1, GFP_KERNEL);
+        if (!buf)
                 return -ENOMEM;
 
-        if (copy_from_user(input_string, buffer, count)) {
-                kfree(input_string);
-                return -EFAULT;
-        }
-        input_string[count] = '\0';
+        ret = -EFAULT;
+        if (copy_from_user(buf, buffer, count))
+                goto out;
 
-        strstrip(input_string);
+        buf[count] = '\0';
+        input_string = strstrip(buf);
 
         /*
          * Clear all breakpoints if:
@@ -302,15 +301,13 @@ static ssize_t ksym_trace_filter_write(struct file *file,
         if (!input_string[0] || !strcmp(input_string, "0") ||
             !strcmp(input_string, "*:---")) {
                 __ksym_trace_reset();
-                kfree(input_string);
-                return count;
+                ret = 0;
+                goto out;
         }
 
         ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
-        if (ret < 0) {
-                kfree(input_string);
-                return ret;
-        }
+        if (ret < 0)
+                goto out;
 
         mutex_lock(&ksym_tracer_mutex);
 
@@ -321,7 +318,7 @@ static ssize_t ksym_trace_filter_write(struct file *file,
                         if (entry->attr.bp_type != op)
                                 changed = 1;
                         else
-                                goto out;
+                                goto out_unlock;
                         break;
                 }
         }
@@ -336,28 +333,24 @@ static ssize_t ksym_trace_filter_write(struct file *file,
                         if (IS_ERR(entry->ksym_hbp))
                                 ret = PTR_ERR(entry->ksym_hbp);
                         else
-                                goto out;
+                                goto out_unlock;
                 }
                 /* Error or "symbol:---" case: drop it */
                 ksym_filter_entry_count--;
                 hlist_del_rcu(&(entry->ksym_hlist));
                 synchronize_rcu();
                 kfree(entry);
-                goto out;
+                goto out_unlock;
         } else {
                 /* Check for malformed request: (4) */
-                if (op == 0)
-                        goto out;
-                ret = process_new_ksym_entry(ksymname, op, ksym_addr);
+                if (op)
+                        ret = process_new_ksym_entry(ksymname, op, ksym_addr);
         }
-out:
+out_unlock:
         mutex_unlock(&ksym_tracer_mutex);
-
-        kfree(input_string);
-
-        if (!ret)
-                ret = count;
-        return ret;
+out:
+        kfree(buf);
+        return !ret ? count : ret;
 }
 
 static const struct file_operations ksym_tracing_fops = {