diff options
| -rw-r--r-- | kernel/trace/trace.h | 3 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 55 |
2 files changed, 54 insertions, 4 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 7944b929459..51b44483eb7 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -226,6 +226,9 @@ extern struct list_head ftrace_trace_arrays; extern struct mutex trace_types_lock; +extern int trace_array_get(struct trace_array *tr); +extern void trace_array_put(struct trace_array *tr); + /* * The global tracer (top) should be the first trace array added, * but we check the flag anyway. diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 32b9895af23..6dfd48b5d1c 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -413,6 +413,35 @@ static void put_system(struct ftrace_subsystem_dir *dir) } /* + * Open and update trace_array ref count. + * Must have the current trace_array passed to it. + */ +static int tracing_open_generic_file(struct inode *inode, struct file *filp) +{ + struct ftrace_event_file *file = inode->i_private; + struct trace_array *tr = file->tr; + int ret; + + if (trace_array_get(tr) < 0) + return -ENODEV; + + ret = tracing_open_generic(inode, filp); + if (ret < 0) + trace_array_put(tr); + return ret; +} + +static int tracing_release_generic_file(struct inode *inode, struct file *filp) +{ + struct ftrace_event_file *file = inode->i_private; + struct trace_array *tr = file->tr; + + trace_array_put(tr); + + return 0; +} + +/* * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. */ static int @@ -1046,9 +1075,17 @@ static int subsystem_open(struct inode *inode, struct file *filp) /* Some versions of gcc think dir can be uninitialized here */ WARN_ON(!dir); + /* Still need to increment the ref count of the system */ + if (trace_array_get(tr) < 0) { + put_system(dir); + return -ENODEV; + } + ret = tracing_open_generic(inode, filp); - if (ret < 0) + if (ret < 0) { + trace_array_put(tr); put_system(dir); + } return ret; } @@ -1059,16 +1096,23 @@ static int system_tr_open(struct inode *inode, struct file *filp) struct trace_array *tr = inode->i_private; int ret; + if (trace_array_get(tr) < 0) + return -ENODEV; + /* Make a temporary dir that has no system but points to tr */ dir = kzalloc(sizeof(*dir), GFP_KERNEL); - if (!dir) + if (!dir) { + trace_array_put(tr); return -ENOMEM; + } dir->tr = tr; ret = tracing_open_generic(inode, filp); - if (ret < 0) + if (ret < 0) { + trace_array_put(tr); kfree(dir); + } filp->private_data = dir; @@ -1079,6 +1123,8 @@ static int subsystem_release(struct inode *inode, struct file *file) { struct ftrace_subsystem_dir *dir = file->private_data; + trace_array_put(dir->tr); + /* * If dir->subsystem is NULL, then this is a temporary * descriptor that was made for a trace_array to enable @@ -1206,9 +1252,10 @@ static const struct file_operations ftrace_set_event_fops = { }; static const struct file_operations ftrace_enable_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_file, .read = event_enable_read, .write = event_enable_write, + .release = tracing_release_generic_file, .llseek = default_llseek, }; |