diff options
| -rw-r--r-- | kernel/trace/trace_events.c | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 302a9f148c8..83ff94a475b 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -495,7 +495,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { const char set_to_char[4] = { '?', '0', '1', 'X' }; - const char *system = filp->private_data; + struct event_subsystem *system = filp->private_data; struct ftrace_event_call *call; char buf[2]; int set = 0; @@ -507,7 +507,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, (!call->class->probe && !call->class->reg)) continue; - if (system && strcmp(call->class->system, system) != 0) + if (system && strcmp(call->class->system, system->name) != 0) continue; /* @@ -537,7 +537,8 @@ static ssize_t system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - const char *system = filp->private_data; + struct event_subsystem *system = filp->private_data; + const char *name = NULL; unsigned long val; char buf[64]; ssize_t ret; @@ -561,7 +562,14 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, if (val != 0 && val != 1) return -EINVAL; - ret = __ftrace_set_clr_event(NULL, system, NULL, val); + /* + * Opening of "enable" adds a ref count to system, + * so the name is safe to use. + */ + if (system) + name = system->name; + + ret = __ftrace_set_clr_event(NULL, name, NULL, val); if (ret) goto out; @@ -740,6 +748,9 @@ static int subsystem_open(struct inode *inode, struct file *filp) struct event_subsystem *system = NULL; int ret; + if (!inode->i_private) + goto skip_search; + /* Make sure the system still exists */ mutex_lock(&event_mutex); list_for_each_entry(system, &event_subsystems, list) { @@ -758,8 +769,9 @@ static int subsystem_open(struct inode *inode, struct file *filp) if (system != inode->i_private) return -ENODEV; + skip_search: ret = tracing_open_generic(inode, filp); - if (ret < 0) + if (ret < 0 && system) put_system(system); return ret; @@ -769,7 +781,8 @@ static int subsystem_release(struct inode *inode, struct file *file) { struct event_subsystem *system = inode->i_private; - put_system(system); + if (system) + put_system(system); return 0; } @@ -913,9 +926,10 @@ static const struct file_operations ftrace_subsystem_filter_fops = { }; static const struct file_operations ftrace_system_enable_fops = { - .open = tracing_open_generic, + .open = subsystem_open, .read = system_enable_read, .write = system_enable_write, + .release = subsystem_release, }; static const struct file_operations ftrace_show_header_fops = { @@ -1003,8 +1017,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events) "'%s/filter' entry\n", name); } - trace_create_file("enable", 0644, system->entry, - (void *)system->name, + trace_create_file("enable", 0644, system->entry, system, &ftrace_system_enable_fops); return system->entry; |