aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--include/linux/ftrace.h1
-rw-r--r--include/linux/kernel.h1
-rw-r--r--kernel/extable.c8
-rw-r--r--kernel/trace/ftrace.c37
4 files changed, 40 insertions, 7 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4609c0ece79a..caba694a62b6 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -34,6 +34,7 @@ struct ftrace_hash;
enum {
FTRACE_OPS_FL_ENABLED = 1 << 0,
FTRACE_OPS_FL_GLOBAL = 1 << 1,
+ FTRACE_OPS_FL_DYNAMIC = 1 << 2,
};
struct ftrace_ops {
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 00cec4dc0ae2..f37ba716ef8b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -283,6 +283,7 @@ extern char *get_options(const char *str, int nints, int *ints);
extern unsigned long long memparse(const char *ptr, char **retptr);
extern int core_kernel_text(unsigned long addr);
+extern int core_kernel_data(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
extern int func_ptr_is_kernel_text(void *ptr);
diff --git a/kernel/extable.c b/kernel/extable.c
index 7f8f263f8524..c2d625fcda77 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -72,6 +72,14 @@ int core_kernel_text(unsigned long addr)
return 0;
}
+int core_kernel_data(unsigned long addr)
+{
+ if (addr >= (unsigned long)_sdata &&
+ addr < (unsigned long)_edata)
+ return 1;
+ return 0;
+}
+
int __kernel_text_address(unsigned long addr)
{
if (core_kernel_text(addr))
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6c7e1df39b57..5b3ee04e39d9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -189,8 +189,14 @@ static void update_ftrace_function(void)
update_global_ops();
+ /*
+ * If we are at the end of the list and this ops is
+ * not dynamic, then have the mcount trampoline call
+ * the function directly
+ */
if (ftrace_ops_list == &ftrace_list_end ||
- ftrace_ops_list->next == &ftrace_list_end)
+ (ftrace_ops_list->next == &ftrace_list_end &&
+ !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
func = ftrace_ops_list->func;
else
func = ftrace_ops_list_func;
@@ -250,6 +256,9 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
return -EBUSY;
+ if (!core_kernel_data((unsigned long)ops))
+ ops->flags |= FTRACE_OPS_FL_DYNAMIC;
+
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
int first = ftrace_global_list == &ftrace_list_end;
add_ftrace_ops(&ftrace_global_list, ops);
@@ -293,6 +302,13 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (ftrace_enabled)
update_ftrace_function();
+ /*
+ * Dynamic ops may be freed, we must make sure that all
+ * callers are done before leaving this function.
+ */
+ if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+ synchronize_sched();
+
return 0;
}
@@ -1225,6 +1241,9 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
* the filter_hash does not exist or is empty,
* AND
* the ip is not in the ops->notrace_hash.
+ *
+ * This needs to be called with preemption disabled as
+ * the hashes are freed with call_rcu_sched().
*/
static int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
@@ -1233,9 +1252,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
struct ftrace_hash *notrace_hash;
int ret;
- /* The hashes are freed with call_rcu_sched() */
- preempt_disable_notrace();
-
filter_hash = rcu_dereference_raw(ops->filter_hash);
notrace_hash = rcu_dereference_raw(ops->notrace_hash);
@@ -1246,7 +1262,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
ret = 1;
else
ret = 0;
- preempt_enable_notrace();
return ret;
}
@@ -3425,14 +3440,20 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
static void
ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
{
- /* see comment above ftrace_global_list_func */
- struct ftrace_ops *op = rcu_dereference_raw(ftrace_ops_list);
+ struct ftrace_ops *op;
+ /*
+ * Some of the ops may be dynamically allocated,
+ * they must be freed after a synchronize_sched().
+ */
+ preempt_disable_notrace();
+ op = rcu_dereference_raw(ftrace_ops_list);
while (op != &ftrace_list_end) {
if (ftrace_ops_test(op, ip))
op->func(ip, parent_ip);
op = rcu_dereference_raw(op->next);
};
+ preempt_enable_notrace();
}
static void clear_ftrace_swapper(void)
@@ -3743,6 +3764,7 @@ int register_ftrace_function(struct ftrace_ops *ops)
mutex_unlock(&ftrace_lock);
return ret;
}
+EXPORT_SYMBOL_GPL(register_ftrace_function);
/**
* unregister_ftrace_function - unregister a function for profiling.
@@ -3762,6 +3784,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
return ret;
}
+EXPORT_SYMBOL_GPL(unregister_ftrace_function);
int
ftrace_enable_sysctl(struct ctl_table *table, int write,