1 files changed, 37 insertions, 17 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fb186b9ddf51..31c90fec4158 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1925,8 +1925,16 @@ ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
          * when we are adding another op to the rec or removing the
          * current one. Thus, if the op is being added, we can
          * ignore it because it hasn't attached itself to the rec
-         * yet. That means we just need to find the op that has a
-         * trampoline and is not beeing added.
+         * yet.
+         *
+         * If an ops is being modified (hooking to different functions)
+         * then we don't care about the new functions that are being
+         * added, just the old ones (that are probably being removed).
+         *
+         * If we are adding an ops to a function that already is using
+         * a trampoline, it needs to be removed (trampolines are only
+         * for single ops connected), then an ops that is not being
+         * modified also needs to be checked.
          */
         do_for_each_ftrace_op(op, ftrace_ops_list) {
 
@@ -1940,17 +1948,23 @@ ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
                 if (op->flags & FTRACE_OPS_FL_ADDING)
                         continue;
 
+
                 /*
-                 * If the ops is not being added and has a trampoline,
-                 * then it must be the one that we want!
+                 * If the ops is being modified and is in the old
+                 * hash, then it is probably being removed from this
+                 * function.
                  */
-                if (hash_contains_ip(ip, op->func_hash))
-                        return op;
-
-                /* If the ops is being modified, it may be in the old hash. */
                 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
                     hash_contains_ip(ip, &op->old_hash))
                         return op;
+                /*
+                 * If the ops is not being added or modified, and it's
+                 * in its normal filter hash, then this must be the one
+                 * we want!
+                 */
+                if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
+                    hash_contains_ip(ip, op->func_hash))
+                        return op;
 
         } while_for_each_ftrace_op(op);
 
@@ -2293,10 +2307,13 @@ static void ftrace_run_update_code(int command)
         FTRACE_WARN_ON(ret);
 }
 
-static void ftrace_run_modify_code(struct ftrace_ops *ops, int command)
+static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
+                                   struct ftrace_hash *old_hash)
 {
         ops->flags |= FTRACE_OPS_FL_MODIFYING;
+        ops->old_hash.filter_hash = old_hash;
         ftrace_run_update_code(command);
+        ops->old_hash.filter_hash = NULL;
         ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
 }
 
@@ -3340,7 +3357,7 @@ static struct ftrace_ops trace_probe_ops __read_mostly =
 
 static int ftrace_probe_registered;
 
-static void __enable_ftrace_function_probe(void)
+static void __enable_ftrace_function_probe(struct ftrace_hash *old_hash)
 {
         int ret;
         int i;
@@ -3348,7 +3365,8 @@ static void __enable_ftrace_function_probe(void)
         if (ftrace_probe_registered) {
                 /* still need to update the function call sites */
                 if (ftrace_enabled)
-                        ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS);
+                        ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
+                                               old_hash);
                 return;
         }
 
@@ -3477,13 +3495,14 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
         } while_for_each_ftrace_rec();
 
         ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
+
+        __enable_ftrace_function_probe(old_hash);
+
         if (!ret)
                 free_ftrace_hash_rcu(old_hash);
         else
                 count = ret;
 
-        __enable_ftrace_function_probe();
-
  out_unlock:
         mutex_unlock(&ftrace_lock);
  out:
@@ -3764,10 +3783,11 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
         return add_hash_entry(hash, ip);
 }
 
-static void ftrace_ops_update_code(struct ftrace_ops *ops)
+static void ftrace_ops_update_code(struct ftrace_ops *ops,
+                                   struct ftrace_hash *old_hash)
 {
         if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
-                ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS);
+                ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
 }
 
 static int
@@ -3813,7 +3833,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
         old_hash = *orig_hash;
         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
         if (!ret) {
-                ftrace_ops_update_code(ops);
+                ftrace_ops_update_code(ops, old_hash);
                 free_ftrace_hash_rcu(old_hash);
         }
         mutex_unlock(&ftrace_lock);
@@ -4058,7 +4078,7 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
                 ret = ftrace_hash_move(iter->ops, filter_hash,
                                        orig_hash, iter->hash);
                 if (!ret) {
-                        ftrace_ops_update_code(iter->ops);
+                        ftrace_ops_update_code(iter->ops, old_hash);
                         free_ftrace_hash_rcu(old_hash);
                 }
                 mutex_unlock(&ftrace_lock);