diff options
| -rw-r--r-- | kernel/trace/trace.c | 68 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 33 |
3 files changed, 102 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 07a63114d938..ab3df804fa96 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5192,6 +5192,42 @@ static int new_instance_create(const char *name) } +static int instance_delete(const char *name) +{ + struct trace_array *tr; + int found = 0; + int ret; + + mutex_lock(&trace_types_lock); + + ret = -ENODEV; + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr->name && strcmp(tr->name, name) == 0) { + found = 1; + break; + } + } + if (!found) + goto out_unlock; + + list_del(&tr->list); + + event_trace_del_tracer(tr); + debugfs_remove_recursive(tr->dir); + free_percpu(tr->data); + ring_buffer_free(tr->buffer); + + kfree(tr->name); + kfree(tr); + + ret = 0; + + out_unlock: + mutex_unlock(&trace_types_lock); + + return ret; +} + static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode) { struct dentry *parent; @@ -5219,9 +5255,41 @@ static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t m return ret; } +static int instance_rmdir(struct inode *inode, struct dentry *dentry) +{ + struct dentry *parent; + int ret; + + /* Paranoid: Make sure the parent is the "instances" directory */ + parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); + if (WARN_ON_ONCE(parent != trace_instance_dir)) + return -ENOENT; + + /* The caller did a dget() on dentry */ + mutex_unlock(&dentry->d_inode->i_mutex); + + /* + * The inode mutex is locked, but debugfs_create_dir() will also + * take the mutex. As the instances directory can not be destroyed + * or changed in any other way, it is safe to unlock it, and + * let the dentry try. If two users try to make the same dir at + * the same time, then the instance_delete() will determine the + * winner. + */ + mutex_unlock(&inode->i_mutex); + + ret = instance_delete(dentry->d_iname); + + mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT); + mutex_lock(&dentry->d_inode->i_mutex); + + return ret; +} + static const struct inode_operations instance_dir_inode_operations = { .lookup = simple_lookup, .mkdir = instance_mkdir, + .rmdir = instance_rmdir, }; static __init void create_trace_instances(struct dentry *d_tracer) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 883fe0b62f0a..b825ea2d8c64 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1001,6 +1001,7 @@ filter_check_discard(struct ftrace_event_call *call, void *rec, extern void trace_event_enable_cmd_record(bool enable); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); +extern int event_trace_del_tracer(struct trace_array *tr); extern struct mutex event_mutex; extern struct list_head ftrace_events; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 58a61302a733..06d6bc275221 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1709,6 +1709,20 @@ __trace_add_event_dirs(struct trace_array *tr) } } +/* Remove the event directory structure for a trace directory. */ +static void +__trace_remove_event_dirs(struct trace_array *tr) +{ + struct ftrace_event_file *file, *next; + + list_for_each_entry_safe(file, next, &tr->events, list) { + list_del(&file->list); + debugfs_remove_recursive(file->dir); + remove_subsystem(file->system); + kfree(file); + } +} + static void __add_event_to_tracers(struct ftrace_event_call *call, struct ftrace_module_file_ops *file_ops) @@ -1793,6 +1807,25 @@ int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr) return 0; } +int event_trace_del_tracer(struct trace_array *tr) +{ + /* Disable any running events */ + __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0); + + mutex_lock(&event_mutex); + + down_write(&trace_event_mutex); + __trace_remove_event_dirs(tr); + debugfs_remove_recursive(tr->event_dir); + up_write(&trace_event_mutex); + + tr->event_dir = NULL; + + mutex_unlock(&event_mutex); + + return 0; +} + static __init int event_trace_enable(void) { struct trace_array *tr = top_trace_array(); |