diff options
| -rw-r--r-- | include/linux/ftrace.h | 1 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 5 | ||||
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 35 |
3 files changed, 36 insertions, 5 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4807a39e7ae1..18fb2c4a3f7f 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -760,6 +760,7 @@ extern char __irqentry_text_end[]; extern int register_ftrace_graph(trace_func_graph_ret_t retfunc, trace_func_graph_ent_t entryfunc); +extern bool ftrace_graph_is_dead(void); extern void ftrace_graph_stop(void); /* The current handlers in use */ diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1776153ea6e0..8063280fd53d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5473,9 +5473,4 @@ void ftrace_graph_exit_task(struct task_struct *t) kfree(ret_stack); } - -void ftrace_graph_stop(void) -{ - ftrace_stop(); -} #endif diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 4de3e57f723c..3604690be70b 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -15,6 +15,38 @@ #include "trace.h" #include "trace_output.h" +static bool kill_ftrace_graph; + +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +bool ftrace_graph_is_dead(void) +{ + return kill_ftrace_graph; +} + +/** + * ftrace_graph_stop - set to permanently disable function graph tracincg + * + * In case of an error int function graph tracing, this is called + * to try to keep function graph tracing from causing any more harm. + * Usually this is pretty severe and this is called to try to at least + * get a warning out to the user. + */ +void ftrace_graph_stop(void) +{ + kill_ftrace_graph = true; + /* + * ftrace_stop() will be removed when all archs are updated to + * use ftrace_graph_is_dead() + */ + ftrace_stop(); +} + /* When set, irq functions will be ignored */ static int ftrace_graph_skip_irqs; @@ -92,6 +124,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long long calltime; int index; + if (unlikely(ftrace_graph_is_dead())) + return -EBUSY; + if (!current->ret_stack) return -EBUSY; |
