[for-next][PATCH 5/6] tracing: Fix trace events build without modules
From: "Steven Rostedt (Red Hat)" The new multi-buffers added a descriptor that kept track of module events, and the directories they use, with struct ftace_module_file_ops. This is used to add a ref count to keep modules from unloading while their files are being accessed. As the descriptor is only needed when CONFIG_MODULES is enabled, it is only declared when the config is enabled. But that struct is dereferenced in a few areas outside the #ifdef CONFIG_MODULES. By adding some helper routines and moving code around a little, events can be compiled again without modules. Reported-by: Fengguang Wu Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 55 --- 1 file changed, 36 insertions(+), 19 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 63b4bdf..0f1307a 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1546,9 +1546,18 @@ struct ftrace_module_file_ops { struct file_operations filter; }; -static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod) +static struct ftrace_module_file_ops * +find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod) { - struct ftrace_module_file_ops *file_ops; + /* +* As event_calls are added in groups by module, +* when we find one file_ops, we don't need to search for +* each call in that module, as the rest should be the +* same. Only search for a new one if the last one did +* not match. +*/ + if (file_ops && mod == file_ops->mod) + return file_ops; list_for_each_entry(file_ops, _module_file_list, list) { if (file_ops->mod == mod) @@ -1664,16 +1673,35 @@ static int trace_module_notify(struct notifier_block *self, return 0; } + +static int +__trace_add_new_mod_event(struct ftrace_event_call *call, + struct trace_array *tr, + struct ftrace_module_file_ops *file_ops) +{ + return __trace_add_new_event(call, tr, +_ops->id, _ops->enable, +_ops->filter, _ops->format); +} + #else -static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod) +static inline struct ftrace_module_file_ops * +find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod) { return NULL; } -static int trace_module_notify(struct notifier_block *self, - unsigned long val, void *data) +static inline int trace_module_notify(struct notifier_block *self, + unsigned long val, void *data) { return 0; } +static inline int +__trace_add_new_mod_event(struct ftrace_event_call *call, + struct trace_array *tr, + struct ftrace_module_file_ops *file_ops) +{ + return -ENODEV; +} #endif /* CONFIG_MODULES */ /* Create a new event directory structure for a trace directory. */ @@ -1692,20 +1720,11 @@ __trace_add_event_dirs(struct trace_array *tr) * want the module to disappear when reading one * of these files). The file_ops keep account of * the module ref count. -* -* As event_calls are added in groups by module, -* when we find one file_ops, we don't need to search for -* each call in that module, as the rest should be the -* same. Only search for a new one if the last one did -* not match. */ - if (!file_ops || call->mod != file_ops->mod) - file_ops = find_ftrace_file_ops(call->mod); + file_ops = find_ftrace_file_ops(file_ops, call->mod); if (!file_ops) continue; /* Warn? */ - ret = __trace_add_new_event(call, tr, - _ops->id, _ops->enable, - _ops->filter, _ops->format); + ret = __trace_add_new_mod_event(call, tr, file_ops); if (ret < 0) pr_warning("Could not create directory for event %s\n", call->name); @@ -1794,9 +1813,7 @@ __add_event_to_tracers(struct ftrace_event_call *call, list_for_each_entry(tr, _trace_arrays, list) { if (file_ops) - __trace_add_new_event(call, tr, - _ops->id, _ops->enable, - _ops->filter, _ops->format); + __trace_add_new_mod_event(call, tr,
[for-next][PATCH 5/6] tracing: Fix trace events build without modules
From: Steven Rostedt (Red Hat) srost...@redhat.com The new multi-buffers added a descriptor that kept track of module events, and the directories they use, with struct ftace_module_file_ops. This is used to add a ref count to keep modules from unloading while their files are being accessed. As the descriptor is only needed when CONFIG_MODULES is enabled, it is only declared when the config is enabled. But that struct is dereferenced in a few areas outside the #ifdef CONFIG_MODULES. By adding some helper routines and moving code around a little, events can be compiled again without modules. Reported-by: Fengguang Wu fengguang...@intel.com Signed-off-by: Steven Rostedt rost...@goodmis.org --- kernel/trace/trace_events.c | 55 --- 1 file changed, 36 insertions(+), 19 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 63b4bdf..0f1307a 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1546,9 +1546,18 @@ struct ftrace_module_file_ops { struct file_operations filter; }; -static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod) +static struct ftrace_module_file_ops * +find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod) { - struct ftrace_module_file_ops *file_ops; + /* +* As event_calls are added in groups by module, +* when we find one file_ops, we don't need to search for +* each call in that module, as the rest should be the +* same. Only search for a new one if the last one did +* not match. +*/ + if (file_ops mod == file_ops-mod) + return file_ops; list_for_each_entry(file_ops, ftrace_module_file_list, list) { if (file_ops-mod == mod) @@ -1664,16 +1673,35 @@ static int trace_module_notify(struct notifier_block *self, return 0; } + +static int +__trace_add_new_mod_event(struct ftrace_event_call *call, + struct trace_array *tr, + struct ftrace_module_file_ops *file_ops) +{ + return __trace_add_new_event(call, tr, +file_ops-id, file_ops-enable, +file_ops-filter, file_ops-format); +} + #else -static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod) +static inline struct ftrace_module_file_ops * +find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod) { return NULL; } -static int trace_module_notify(struct notifier_block *self, - unsigned long val, void *data) +static inline int trace_module_notify(struct notifier_block *self, + unsigned long val, void *data) { return 0; } +static inline int +__trace_add_new_mod_event(struct ftrace_event_call *call, + struct trace_array *tr, + struct ftrace_module_file_ops *file_ops) +{ + return -ENODEV; +} #endif /* CONFIG_MODULES */ /* Create a new event directory structure for a trace directory. */ @@ -1692,20 +1720,11 @@ __trace_add_event_dirs(struct trace_array *tr) * want the module to disappear when reading one * of these files). The file_ops keep account of * the module ref count. -* -* As event_calls are added in groups by module, -* when we find one file_ops, we don't need to search for -* each call in that module, as the rest should be the -* same. Only search for a new one if the last one did -* not match. */ - if (!file_ops || call-mod != file_ops-mod) - file_ops = find_ftrace_file_ops(call-mod); + file_ops = find_ftrace_file_ops(file_ops, call-mod); if (!file_ops) continue; /* Warn? */ - ret = __trace_add_new_event(call, tr, - file_ops-id, file_ops-enable, - file_ops-filter, file_ops-format); + ret = __trace_add_new_mod_event(call, tr, file_ops); if (ret 0) pr_warning(Could not create directory for event %s\n, call-name); @@ -1794,9 +1813,7 @@ __add_event_to_tracers(struct ftrace_event_call *call, list_for_each_entry(tr, ftrace_trace_arrays, list) { if (file_ops) - __trace_add_new_event(call, tr, - file_ops-id, file_ops-enable, -