Merge branch 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh...

[firefly-linux-kernel-4.4.55.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d017c2c82c44a084fcfc88faf7c88b32463a82c4..908038f57440e5eec44233351578105ff8c64e08 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -109,12 +109,18 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
 static void ftrace_global_list_func(unsigned long ip,
                                    unsigned long parent_ip)
 {
-       struct ftrace_ops *op = rcu_dereference_raw(ftrace_global_list); /*see above*/
+       struct ftrace_ops *op;
+
+       if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
+               return;
 
+       trace_recursion_set(TRACE_GLOBAL_BIT);
+       op = rcu_dereference_raw(ftrace_global_list); /*see above*/
        while (op != &ftrace_list_end) {
                op->func(ip, parent_ip);
                op = rcu_dereference_raw(op->next); /*see above*/
        };
+       trace_recursion_clear(TRACE_GLOBAL_BIT);
 }
 
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
@@ -1638,12 +1644,12 @@ static void ftrace_startup_enable(int command)
        ftrace_run_update_code(command);
 }
 
-static void ftrace_startup(struct ftrace_ops *ops, int command)
+static int ftrace_startup(struct ftrace_ops *ops, int command)
 {
        bool hash_enable = true;
 
        if (unlikely(ftrace_disabled))
-               return;
+               return -ENODEV;
 
        ftrace_start_up++;
        command |= FTRACE_ENABLE_CALLS;
@@ -1662,6 +1668,8 @@ static void ftrace_startup(struct ftrace_ops *ops, int command)
                ftrace_hash_rec_enable(ops, 1);
 
        ftrace_startup_enable(command);
+
+       return 0;
 }
 
 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
@@ -2501,7 +2509,7 @@ static void __enable_ftrace_function_probe(void)
 
        ret = __register_ftrace_function(&trace_probe_ops);
        if (!ret)
-               ftrace_startup(&trace_probe_ops, 0);
+               ret = ftrace_startup(&trace_probe_ops, 0);
 
        ftrace_probe_registered = 1;
 }
@@ -2732,7 +2740,7 @@ static int ftrace_process_regex(struct ftrace_hash *hash,
 {
        char *func, *command, *next = buff;
        struct ftrace_func_command *p;
-       int ret;
+       int ret = -EINVAL;
 
        func = strsep(&next, ":");
 
@@ -3322,6 +3330,7 @@ static int ftrace_process_locs(struct module *mod,
 {
        unsigned long *p;
        unsigned long addr;
+       unsigned long flags;
 
        mutex_lock(&ftrace_lock);
        p = start;
@@ -3338,7 +3347,13 @@ static int ftrace_process_locs(struct module *mod,
                ftrace_record_ip(addr);
        }
 
+       /*
+        * Disable interrupts to prevent interrupts from executing
+        * code that is being modified.
+        */
+       local_irq_save(flags);
        ftrace_update_code(mod);
+       local_irq_restore(flags);
        mutex_unlock(&ftrace_lock);
 
        return 0;
@@ -3466,7 +3481,11 @@ device_initcall(ftrace_nodyn_init);
 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
 static inline void ftrace_startup_enable(int command) { }
 /* Keep as macros so we do not need to define the commands */
-# define ftrace_startup(ops, command)  do { } while (0)
+# define ftrace_startup(ops, command)                  \
+       ({                                              \
+               (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
+               0;                                      \
+       })
 # define ftrace_shutdown(ops, command) do { } while (0)
 # define ftrace_startup_sysctl()       do { } while (0)
 # define ftrace_shutdown_sysctl()      do { } while (0)
@@ -3484,6 +3503,10 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
 {
        struct ftrace_ops *op;
 
+       if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
+               return;
+
+       trace_recursion_set(TRACE_INTERNAL_BIT);
        /*
         * Some of the ops may be dynamically allocated,
         * they must be freed after a synchronize_sched().
@@ -3496,6 +3519,7 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
                op = rcu_dereference_raw(op->next);
        };
        preempt_enable_notrace();
+       trace_recursion_clear(TRACE_INTERNAL_BIT);
 }
 
 static void clear_ftrace_swapper(void)
@@ -3799,7 +3823,7 @@ int register_ftrace_function(struct ftrace_ops *ops)
 
        ret = __register_ftrace_function(ops);
        if (!ret)
-               ftrace_startup(ops, 0);
+               ret = ftrace_startup(ops, 0);
 
 
  out_unlock:
@@ -4045,7 +4069,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
        ftrace_graph_return = retfunc;
        ftrace_graph_entry = entryfunc;
 
-       ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
+       ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
 
 out:
        mutex_unlock(&ftrace_lock);