From: "Steven Rostedt (Red Hat)" Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance directories to let users filter of functions to trace for the given instance. Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 2 ++ kernel/trace/ftrace.c | 39 ++++++++++++++++++++++++++++++++++----- kernel/trace/trace.c | 4 ++++ kernel/trace/trace.h | 25 ++++++++++++++++++++++++- kernel/trace/trace_functions.c | 40 ++++++++++++++++++++++++++++++++-------- 5 files changed, 96 insertions(+), 14 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index ef1607e..e6141be 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -92,6 +92,7 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, * STUB - The ftrace_ops is just a place holder. * INITIALIZED - The ftrace_ops has already been initialized (first use time * register_ftrace_function() is called, it will initialized the ops) + * DELETED - The ops are being deleted, do not let them be registered again. */ enum { FTRACE_OPS_FL_ENABLED = 1 << 0, @@ -103,6 +104,7 @@ enum { FTRACE_OPS_FL_RECURSION_SAFE = 1 << 6, FTRACE_OPS_FL_STUB = 1 << 7, FTRACE_OPS_FL_INITIALIZED = 1 << 8, + FTRACE_OPS_FL_DELETED = 1 << 9, }; /* diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2b3e239..dcee546 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -436,6 +436,9 @@ static int remove_ftrace_list_ops(struct ftrace_ops **list, static int __register_ftrace_function(struct ftrace_ops *ops) { + if (ops->flags & FTRACE_OPS_FL_DELETED) + return -EINVAL; + if (FTRACE_WARN_ON(ops == &global_ops)) return -EINVAL; @@ -4112,6 +4115,36 @@ static const struct file_operations ftrace_graph_notrace_fops = { }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +void ftrace_create_filter_files(struct ftrace_ops *ops, + struct dentry *parent) +{ + + trace_create_file("set_ftrace_filter", 0644, parent, + ops, &ftrace_filter_fops); + + trace_create_file("set_ftrace_notrace", 0644, parent, + ops, &ftrace_notrace_fops); +} + +/* + * The name "destroy_filter_files" is really a misnomer. Although + * in the future, it may actualy delete the files, but this is + * really intended to make sure the ops passed in are disabled + * and that when this function returns, the caller is free to + * free the ops. + * + * The "destroy" name is only to match the "create" name that this + * should be paired with. + */ +void ftrace_destroy_filter_files(struct ftrace_ops *ops) +{ + mutex_lock(&ftrace_lock); + if (ops->flags & FTRACE_OPS_FL_ENABLED) + ftrace_shutdown(ops, 0); + ops->flags |= FTRACE_OPS_FL_DELETED; + mutex_unlock(&ftrace_lock); +} + static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { @@ -4121,11 +4154,7 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) trace_create_file("enabled_functions", 0444, d_tracer, NULL, &ftrace_enabled_fops); - trace_create_file("set_ftrace_filter", 0644, d_tracer, - &global_ops, &ftrace_filter_fops); - - trace_create_file("set_ftrace_notrace", 0644, d_tracer, - &global_ops, &ftrace_notrace_fops); + ftrace_create_filter_files(&global_ops, d_tracer); #ifdef CONFIG_FUNCTION_GRAPH_TRACER trace_create_file("set_graph_function", 0444, d_tracer, diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f9f22c4..d95ec28 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6161,6 +6161,7 @@ static int instance_delete(const char *name) tracing_set_nop(tr); event_trace_del_tracer(tr); + ftrace_destroy_function_files(tr); debugfs_remove_recursive(tr->dir); free_percpu(tr->trace_buffer.data); ring_buffer_free(tr->trace_buffer.buffer); @@ -6291,6 +6292,9 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("tracing_on", 0644, d_tracer, tr, &rb_simple_fops); + if (ftrace_create_function_files(tr, d_tracer)) + WARN(1, "Could not allocate function filter files"); + #ifdef CONFIG_TRACER_SNAPSHOT trace_create_file("snapshot", 0644, d_tracer, tr, &snapshot_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 35cca05..ffc314b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -819,13 +819,36 @@ static inline int ftrace_trace_task(struct task_struct *task) return test_tsk_trace_trace(task); } extern int ftrace_is_dead(void); +int ftrace_create_function_files(struct trace_array *tr, + struct dentry *parent); +void ftrace_destroy_function_files(struct trace_array *tr); #else static inline int ftrace_trace_task(struct task_struct *task) { return 1; } static inline int ftrace_is_dead(void) { return 0; } -#endif +static inline int +ftrace_create_function_files(struct trace_array *tr, + struct dentry *parent) +{ + return 0; +} +static inline void ftrace_destroy_function_files(struct trace_array *tr) { } +#endif /* CONFIG_FUNCTION_TRACER */ + +#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) +void ftrace_create_filter_files(struct ftrace_ops *ops, + struct dentry *parent); +void ftrace_destroy_filter_files(struct ftrace_ops *ops); +#else +/* + * The ops parameter passed in is usually undefined. + * This must be a macro. + */ +#define ftrace_create_filter_files(ops, parent) do { } while (0) +#define ftrace_destroy_filter_files(ops) do { } while (0) +#endif /* CONFIG_FUNCTION_TRACER && CONFIG_DYNAMIC_FTRACE */ int ftrace_event_is_function(struct ftrace_event_call *call); diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 3f8dc1c..5b781d2 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -52,10 +52,34 @@ static int allocate_ftrace_ops(struct trace_array *tr) return 0; } + +int ftrace_create_function_files(struct trace_array *tr, + struct dentry *parent) +{ + int ret; + + /* The top level array uses the "global_ops". */ + if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL)) { + ret = allocate_ftrace_ops(tr); + if (ret) + return ret; + } + + ftrace_create_filter_files(tr->ops, parent); + + return 0; +} + +void ftrace_destroy_function_files(struct trace_array *tr) +{ + ftrace_destroy_filter_files(tr->ops); + kfree(tr->ops); + tr->ops = NULL; +} + static int function_trace_init(struct trace_array *tr) { struct ftrace_ops *ops; - int ret; if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { /* There's only one global tr */ @@ -69,10 +93,13 @@ static int function_trace_init(struct trace_array *tr) else ops = &trace_ops; tr->ops = ops; - } else { - ret = allocate_ftrace_ops(tr); - if (ret) - return ret; + } else if (!tr->ops) { + /* + * Instance trace_arrays get their ops allocated + * at instance creation. Unless it failed + * the allocation. + */ + return -ENOMEM; } tr->trace_buffer.cpu = get_cpu(); @@ -87,9 +114,6 @@ static void function_trace_reset(struct trace_array *tr) { tracing_stop_function_trace(tr); tracing_stop_cmdline_record(); - if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL)) - kfree(tr->ops); - tr->ops = NULL; } static void function_trace_start(struct trace_array *tr) -- 1.8.5.3