1 files changed, 38 insertions, 0 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6233f9102179..fa0f36bb32e9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1117,6 +1117,43 @@ static struct ftrace_ops global_ops = {
                                           FTRACE_OPS_FL_INITIALIZED,
 };
 
+/*
+ * This is used by __kernel_text_address() to return true if the
+ * the address is on a dynamically allocated trampoline that would
+ * not return true for either core_kernel_text() or
+ * is_module_text_address().
+ */
+bool is_ftrace_trampoline(unsigned long addr)
+{
+        struct ftrace_ops *op;
+        bool ret = false;
+
+        /*
+         * Some of the ops may be dynamically allocated,
+         * they are freed after a synchronize_sched().
+         */
+        preempt_disable_notrace();
+
+        do_for_each_ftrace_op(op, ftrace_ops_list) {
+                /*
+                 * This is to check for dynamically allocated trampolines.
+                 * Trampolines that are in kernel text will have
+                 * core_kernel_text() return true.
+                 */
+                if (op->trampoline && op->trampoline_size)
+                        if (addr >= op->trampoline &&
+                            addr < op->trampoline + op->trampoline_size) {
+                                ret = true;
+                                goto out;
+                        }
+        } while_for_each_ftrace_op(op);
+
+ out:
+        preempt_enable_notrace();
+
+        return ret;
+}
+
 struct ftrace_page {
         struct ftrace_page      *next;
         struct dyn_ftrace       *records;
@@ -5373,6 +5410,7 @@ static struct ftrace_ops graph_ops = {
                                    FTRACE_OPS_FL_STUB,
 #ifdef FTRACE_GRAPH_TRAMP_ADDR
         .trampoline             = FTRACE_GRAPH_TRAMP_ADDR,
+        /* trampoline_size is only needed for dynamically allocated tramps */
 #endif
         ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
 };