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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.
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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
This commit is contained in:
Linus Torvalds 2013-11-26 18:04:21 -08:00
parent 4f9e5df211 8a56d7761d
commit 8ae516aa8b
2 changed files with 38 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/trace/ftrace.h
View File

@ -372,7 +372,8 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \
__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 @@ static inline notrace int ftrace_get_offsets_##call( \
#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

64
kernel/trace/ftrace.c
View File

@ -367,9 +367,6 @@ static int remove_ftrace_list_ops(struct ftrace_ops **list,
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 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
{
int ret;
if (ftrace_disabled)
return -ENODEV;
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
@ -2088,10 +2082,15 @@ static void ftrace_startup_enable(int command)
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 @@ static int ftrace_startup(struct ftrace_ops *ops, int command)
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 @@ static void ftrace_shutdown(struct ftrace_ops *ops, int command)
}
if (!command || !ftrace_enabled)
return;
return 0;
ftrace_run_update_code(command);
return 0;
}
static void ftrace_startup_sysctl(void)
@ -3060,16 +3065,13 @@ static void __enable_ftrace_function_probe(void)
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 @@ static void __disable_ftrace_function_probe(void)
}
/* 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 @@ core_initcall(ftrace_nodyn_init);
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 @@ int register_ftrace_function(struct ftrace_ops *ops)
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 unregister_ftrace_function(struct ftrace_ops *ops)
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 @@ ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
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 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
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 @@ void unregister_ftrace_graph(void)
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);