7 files changed, 74 insertions, 36 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 9c89526b6b7..b8378fad29a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -59,7 +59,6 @@ config FUNCTION_TRACER
 
 config FUNCTION_RET_TRACER
         bool "Kernel Function return Tracer"
-        depends on !DYNAMIC_FTRACE
         depends on HAVE_FUNCTION_RET_TRACER
         depends on FUNCTION_TRACER
         help
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b42ec1de546..f212da48668 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -50,6 +50,9 @@ static int last_ftrace_enabled;
 /* Quick disabling of function tracer. */
 int function_trace_stop;
 
+/* By default, current tracing type is normal tracing. */
+enum ftrace_tracing_type_t ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
 /*
  * ftrace_disabled is set when an anomaly is discovered.
  * ftrace_disabled is much stronger than ftrace_enabled.
@@ -385,12 +388,21 @@ static void ftrace_bug(int failed, unsigned long ip)
         }
 }
 
-#define FTRACE_ADDR ((long)(ftrace_caller))
 
 static int
 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 {
         unsigned long ip, fl;
+        unsigned long ftrace_addr;
+
+#ifdef CONFIG_FUNCTION_RET_TRACER
+        if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
+                ftrace_addr = (unsigned long)ftrace_caller;
+        else
+                ftrace_addr = (unsigned long)ftrace_return_caller;
+#else
+        ftrace_addr = (unsigned long)ftrace_caller;
+#endif
 
         ip = rec->ip;
 
@@ -450,9 +462,9 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
         }
 
         if (rec->flags & FTRACE_FL_ENABLED)
-                return ftrace_make_call(rec, FTRACE_ADDR);
+                return ftrace_make_call(rec, ftrace_addr);
         else
-                return ftrace_make_nop(NULL, rec, FTRACE_ADDR);
+                return ftrace_make_nop(NULL, rec, ftrace_addr);
 }
 
 static void ftrace_replace_code(int enable)
@@ -682,7 +694,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 
         cnt = num_to_init / ENTRIES_PER_PAGE;
         pr_info("ftrace: allocating %ld entries in %d pages\n",
-                num_to_init, cnt);
+                num_to_init, cnt + 1);
 
         for (i = 0; i < cnt; i++) {
                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -765,13 +777,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
         void *p = NULL;
         loff_t l = -1;
 
-        if (*pos != iter->pos) {
-                for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
-                        ;
-        } else {
-                l = *pos;
-                p = t_next(m, p, &l);
-        }
+        if (*pos > iter->pos)
+                *pos = iter->pos;
+
+        l = *pos;
+        p = t_next(m, p, &l);
 
         return p;
 }
@@ -782,15 +792,21 @@ static void t_stop(struct seq_file *m, void *p)
 
 static int t_show(struct seq_file *m, void *v)
 {
+        struct ftrace_iterator *iter = m->private;
         struct dyn_ftrace *rec = v;
         char str[KSYM_SYMBOL_LEN];
+        int ret = 0;
 
         if (!rec)
                 return 0;
 
         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 
-        seq_printf(m, "%s\n", str);
+        ret = seq_printf(m, "%s\n", str);
+        if (ret < 0) {
+                iter->pos--;
+                iter->idx--;
+        }
 
         return 0;
 }
@@ -816,7 +832,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
                 return -ENOMEM;
 
         iter->pg = ftrace_pages_start;
-        iter->pos = -1;
+        iter->pos = 0;
 
         ret = seq_open(file, &show_ftrace_seq_ops);
         if (!ret) {
@@ -903,7 +919,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
         if (file->f_mode & FMODE_READ) {
                 iter->pg = ftrace_pages_start;
-                iter->pos = -1;
+                iter->pos = 0;
                 iter->flags = enable ? FTRACE_ITER_FILTER :
                         FTRACE_ITER_NOTRACE;
 
@@ -1405,10 +1421,17 @@ int register_ftrace_function(struct ftrace_ops *ops)
                 return -1;
 
         mutex_lock(&ftrace_sysctl_lock);
+
+        if (ftrace_tracing_type == FTRACE_TYPE_RETURN) {
+                ret = -EBUSY;
+                goto out;
+        }
+
         ret = __register_ftrace_function(ops);
         ftrace_startup();
-        mutex_unlock(&ftrace_sysctl_lock);
 
+out:
+        mutex_unlock(&ftrace_sysctl_lock);
         return ret;
 }
 
@@ -1474,16 +1497,45 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_FUNCTION_RET_TRACER
+
+/* The callback that hooks the return of a function */
 trace_function_return_t ftrace_function_return =
                         (trace_function_return_t)ftrace_stub;
-void register_ftrace_return(trace_function_return_t func)
+
+int register_ftrace_return(trace_function_return_t func)
 {
+        int ret = 0;
+
+        mutex_lock(&ftrace_sysctl_lock);
+
+        /*
+         * Don't launch return tracing if normal function
+         * tracing is already running.
+         */
+        if (ftrace_trace_function != ftrace_stub) {
+                ret = -EBUSY;
+                goto out;
+        }
+
+        ftrace_tracing_type = FTRACE_TYPE_RETURN;
         ftrace_function_return = func;
+        ftrace_startup();
+
+out:
+        mutex_unlock(&ftrace_sysctl_lock);
+        return ret;
 }
 
 void unregister_ftrace_return(void)
 {
+        mutex_lock(&ftrace_sysctl_lock);
+
         ftrace_function_return = (trace_function_return_t)ftrace_stub;
+        ftrace_shutdown();
+        /* Restore normal tracing type */
+        ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
+        mutex_unlock(&ftrace_sysctl_lock);
 }
 #endif
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index caa4fda50f8..85ced143c2c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -622,6 +622,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
                 list_del_init(&page->list);
                 free_buffer_page(page);
         }
+        mutex_unlock(&buffer->mutex);
         return -ENOMEM;
 }
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 24b6238884f..5653c6b07ba 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -259,9 +259,7 @@ static const char *trace_options[] = {
         "sched-tree",
         "ftrace_printk",
         "ftrace_preempt",
-#ifdef CONFIG_BRANCH_TRACER
         "branch",
-#endif
         "annotate",
         NULL
 };
@@ -2189,6 +2187,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
                         ring_buffer_read_finish(iter->buffer_iter[cpu]);
         }
         mutex_unlock(&trace_types_lock);
+        kfree(iter);
 
         return ERR_PTR(-ENOMEM);
 }
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index cdbd5cc22be..37947f6b92b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -471,9 +471,7 @@ enum trace_iterator_flags {
         TRACE_ITER_SCHED_TREE           = 0x200,
         TRACE_ITER_PRINTK               = 0x400,
         TRACE_ITER_PREEMPTONLY          = 0x800,
-#ifdef CONFIG_BRANCH_TRACER
         TRACE_ITER_BRANCH               = 0x1000,
-#endif
         TRACE_ITER_ANNOTATE             = 0x2000,
 };
 
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 44bd39539d6..23f9b02ce96 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -41,7 +41,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
         if (unlikely(!tr))
                 return;
 
-        local_irq_save(flags);
+        raw_local_irq_save(flags);
         cpu = raw_smp_processor_id();
         if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
                 goto out;
@@ -73,7 +73,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
 
  out:
         atomic_dec(&tr->data[cpu]->disabled);
-        local_irq_restore(flags);
+        raw_local_irq_restore(flags);
 }
 
 static inline
diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c
index 61185f756a1..a68564af022 100644
--- a/kernel/trace/trace_functions_return.c
+++ b/kernel/trace/trace_functions_return.c
@@ -14,29 +14,18 @@
 #include "trace.h"
 
 
-static void start_return_trace(struct trace_array *tr)
-{
-        register_ftrace_return(&trace_function_return);
-}
-
-static void stop_return_trace(struct trace_array *tr)
-{
-        unregister_ftrace_return();
-}
-
 static int return_trace_init(struct trace_array *tr)
 {
         int cpu;
         for_each_online_cpu(cpu)
                 tracing_reset(tr, cpu);
 
-        start_return_trace(tr);
-        return 0;
+        return register_ftrace_return(&trace_function_return);
 }
 
 static void return_trace_reset(struct trace_array *tr)
 {
-                stop_return_trace(tr);
+                unregister_ftrace_return();
 }