diff options
| -rw-r--r-- | kernel/trace/trace.c | 67 |
1 files changed, 63 insertions, 4 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a946e0183..722d0ba2d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7842,11 +7842,70 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, return cnt; } +/* + * The tr_index is the address of a trace_array->trace_flags_index[] + * element that holds the index of the trace flag. But since the + * trace_array reference has not been taken yet, it cannot be referenced + * as it could have been freed by a rmdir of the instance the trace_array + * represents. + * + * Search the list of trace_arrays and compare the tr_index to the + * address of the entire trace_array trace_flags_index array for each + * trace_array in the list. If one is matched, then take the reference + * and return it. If not, the trace_array no longer exits. + */ +static int trace_array_options_get(void *tr_index) +{ + struct trace_array *tr; + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + if (tracing_disabled) + return -ENODEV; + + guard(mutex)(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr_index >= (void *)&tr->trace_flags_index[0] && + tr_index < (void *)&tr->trace_flags_index[TRACE_FLAGS_MAX_SIZE]) + return __trace_array_get(tr); + } + return -ENODEV; +} + +static int trace_options_open(struct inode *inode, struct file *filp) +{ + void *tr_index = inode->i_private; + + if (trace_array_options_get(tr_index) < 0) + return -ENODEV; + + filp->private_data = tr_index; + + return 0; +} + +static int trace_options_release(struct inode *inode, struct file *filp) +{ + void *tr_index = filp->private_data; + struct trace_array *tr; + unsigned int index; + + get_tr_index(tr_index, &tr, &index); + + trace_array_put(tr); + + return 0; +} + static const struct file_operations trace_options_core_fops = { - .open = tracing_open_generic, - .read = trace_options_core_read, - .write = trace_options_core_write, - .llseek = generic_file_llseek, + .open = trace_options_open, + .read = trace_options_core_read, + .write = trace_options_core_write, + .llseek = generic_file_llseek, + .release = trace_options_release, }; struct dentry *trace_create_file(const char *name, |