ftrace: Fix removing of second function probe

[mirror_ubuntu-zesty-kernel.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index eb230f06ba4123a1dc75dafb508789f6cd7afd25..98775772f7d63cdea32488decb94d5e3bc2a3fae 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3740,23 +3740,24 @@ static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
        ftrace_probe_registered = 1;
 }
 
-static void __disable_ftrace_function_probe(void)
+static bool __disable_ftrace_function_probe(void)
 {
        int i;
 
        if (!ftrace_probe_registered)
-               return;
+               return false;
 
        for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
                struct hlist_head *hhd = &ftrace_func_hash[i];
                if (hhd->first)
-                       return;
+                       return false;
        }
 
        /* no more funcs left */
        ftrace_shutdown(&trace_probe_ops, 0);
 
        ftrace_probe_registered = 0;
+       return true;
 }
 
 
@@ -3886,6 +3887,7 @@ static void
 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                                  void *data, int flags)
 {
+       struct ftrace_ops_hash old_hash_ops;
        struct ftrace_func_entry *rec_entry;
        struct ftrace_func_probe *entry;
        struct ftrace_func_probe *p;
@@ -3897,6 +3899,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
        struct hlist_node *tmp;
        char str[KSYM_SYMBOL_LEN];
        int i, ret;
+       bool disabled;
 
        if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
                func_g.search = NULL;
@@ -3915,6 +3918,10 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
        mutex_lock(&trace_probe_ops.func_hash->regex_lock);
 
+       old_hash_ops.filter_hash = old_hash;
+       /* Probes only have filters */
+       old_hash_ops.notrace_hash = NULL;
+
        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
        if (!hash)
                /* Hmm, should report this somehow */
@@ -3952,12 +3959,17 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                }
        }
        mutex_lock(&ftrace_lock);
-       __disable_ftrace_function_probe();
+       disabled = __disable_ftrace_function_probe();
        /*
         * Remove after the disable is called. Otherwise, if the last
         * probe is removed, a null hash means *all enabled*.
         */
        ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
+
+       /* still need to update the function call sites */
+       if (ftrace_enabled && !disabled)
+               ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
+                                      &old_hash_ops);
        synchronize_sched();
        if (!ret)
                free_ftrace_hash_rcu(old_hash);