Merge tag 'trace-fixes-v3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"This includes two fixes.
1) is a bug fix that happens when root does the following:
echo function_graph > current_tracer
modprobe foo
echo nop > current_tracer
This causes the ftrace internal accounting to get screwed up and
crashes ftrace, preventing the user from using the function tracer
after that.
2) if a TRACE_EVENT has a string field, and NULL is given for it.
The internal trace event code does a strlen() and strcpy() on the
source of field. If it is NULL it causes the system to oops.
This bug has been there since 2.6.31, but no TRACE_EVENT ever passed
in a NULL to the string field, until now"
* tag 'trace-fixes-v3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix function graph with loading of modules
tracing: Allow events to have NULL strings
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 52594b2..d17a35c 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -372,7 +372,8 @@
__data_size += (len) * sizeof(type);
#undef __string
-#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1)
+#define __string(item, src) __dynamic_array(char, item, \
+ strlen((src) ? (const char *)(src) : "(null)") + 1)
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
@@ -501,7 +502,7 @@
#undef __assign_str
#define __assign_str(dst, src) \
- strcpy(__get_str(dst), src);
+ strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)");
#undef TP_fast_assign
#define TP_fast_assign(args...) args
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 22fa556..0e9f9ea 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -367,9 +367,6 @@
static int __register_ftrace_function(struct ftrace_ops *ops)
{
- if (unlikely(ftrace_disabled))
- return -ENODEV;
-
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
@@ -428,9 +425,6 @@
{
int ret;
- if (ftrace_disabled)
- return -ENODEV;
-
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
@@ -2088,10 +2082,15 @@
static int ftrace_startup(struct ftrace_ops *ops, int command)
{
bool hash_enable = true;
+ int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
+ ret = __register_ftrace_function(ops);
+ if (ret)
+ return ret;
+
ftrace_start_up++;
command |= FTRACE_UPDATE_CALLS;
@@ -2113,12 +2112,17 @@
return 0;
}
-static void ftrace_shutdown(struct ftrace_ops *ops, int command)
+static int ftrace_shutdown(struct ftrace_ops *ops, int command)
{
bool hash_disable = true;
+ int ret;
if (unlikely(ftrace_disabled))
- return;
+ return -ENODEV;
+
+ ret = __unregister_ftrace_function(ops);
+ if (ret)
+ return ret;
ftrace_start_up--;
/*
@@ -2153,9 +2157,10 @@
}
if (!command || !ftrace_enabled)
- return;
+ return 0;
ftrace_run_update_code(command);
+ return 0;
}
static void ftrace_startup_sysctl(void)
@@ -3060,16 +3065,13 @@
if (i == FTRACE_FUNC_HASHSIZE)
return;
- ret = __register_ftrace_function(&trace_probe_ops);
- if (!ret)
- ret = ftrace_startup(&trace_probe_ops, 0);
+ ret = ftrace_startup(&trace_probe_ops, 0);
ftrace_probe_registered = 1;
}
static void __disable_ftrace_function_probe(void)
{
- int ret;
int i;
if (!ftrace_probe_registered)
@@ -3082,9 +3084,7 @@
}
/* no more funcs left */
- ret = __unregister_ftrace_function(&trace_probe_ops);
- if (!ret)
- ftrace_shutdown(&trace_probe_ops, 0);
+ ftrace_shutdown(&trace_probe_ops, 0);
ftrace_probe_registered = 0;
}
@@ -4366,12 +4366,15 @@
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) \
- ({ \
- (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
- 0; \
+# define ftrace_startup(ops, command) \
+ ({ \
+ int ___ret = __register_ftrace_function(ops); \
+ if (!___ret) \
+ (ops)->flags |= FTRACE_OPS_FL_ENABLED; \
+ ___ret; \
})
-# define ftrace_shutdown(ops, command) do { } while (0)
+# define ftrace_shutdown(ops, command) __unregister_ftrace_function(ops)
+
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
@@ -4780,9 +4783,7 @@
mutex_lock(&ftrace_lock);
- ret = __register_ftrace_function(ops);
- if (!ret)
- ret = ftrace_startup(ops, 0);
+ ret = ftrace_startup(ops, 0);
mutex_unlock(&ftrace_lock);
@@ -4801,9 +4802,7 @@
int ret;
mutex_lock(&ftrace_lock);
- ret = __unregister_ftrace_function(ops);
- if (!ret)
- ftrace_shutdown(ops, 0);
+ ret = ftrace_shutdown(ops, 0);
mutex_unlock(&ftrace_lock);
return ret;
@@ -4997,6 +4996,13 @@
return NOTIFY_DONE;
}
+/* Just a place holder for function graph */
+static struct ftrace_ops fgraph_ops __read_mostly = {
+ .func = ftrace_stub,
+ .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL |
+ FTRACE_OPS_FL_RECURSION_SAFE,
+};
+
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
trace_func_graph_ent_t entryfunc)
{
@@ -5023,7 +5029,7 @@
ftrace_graph_return = retfunc;
ftrace_graph_entry = entryfunc;
- ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
+ ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET);
out:
mutex_unlock(&ftrace_lock);
@@ -5040,7 +5046,7 @@
ftrace_graph_active--;
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = ftrace_graph_entry_stub;
- ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
+ ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET);
unregister_pm_notifier(&ftrace_suspend_notifier);
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
