diff options
Diffstat (limited to 'kernel/trace/fgraph.c')
| -rw-r--r-- | kernel/trace/fgraph.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 2a42c1036ea8..484ad7a18463 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -815,6 +815,7 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe unsigned long bitmap; unsigned long ret; int offset; + int bit; int i; ret_stack = ftrace_pop_return_trace(&trace, &ret, frame_pointer, &offset); @@ -829,6 +830,15 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe if (fregs) ftrace_regs_set_instruction_pointer(fregs, ret); + bit = ftrace_test_recursion_trylock(trace.func, ret); + /* + * This can fail because ftrace_test_recursion_trylock() allows one nest + * call. If we are already in a nested call, then we don't probe this and + * just return the original return address. + */ + if (unlikely(bit < 0)) + goto out; + #ifdef CONFIG_FUNCTION_GRAPH_RETVAL trace.retval = ftrace_regs_get_return_value(fregs); #endif @@ -852,6 +862,8 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe } } + ftrace_test_recursion_unlock(bit); +out: /* * The ftrace_graph_return() may still access the current * ret_stack structure, we need to make sure the update of @@ -1397,7 +1409,8 @@ error: ftrace_graph_active--; gops->saved_func = NULL; fgraph_lru_release_index(i); - unregister_pm_notifier(&ftrace_suspend_notifier); + if (!ftrace_graph_active) + unregister_pm_notifier(&ftrace_suspend_notifier); } return ret; } |