ftrace: Get a reference counter for the trace_array on filter files
The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for
an instance now. They need to take a reference to the instance otherwise
there could be a race between accessing the files and deleting the instance.
It wasn't until the :mod: caching where these file operations started
referencing the trace_array directly.
Cc: stable@vger.kernel.org
Fixes: 673feb9d76
("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
parent
3ed270b129
commit
9ef16693af
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@ -3540,21 +3540,22 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
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struct ftrace_hash *hash;
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struct list_head *mod_head;
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struct trace_array *tr = ops->private;
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int ret = 0;
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int ret = -ENOMEM;
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ftrace_ops_init(ops);
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if (unlikely(ftrace_disabled))
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return -ENODEV;
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if (tr && trace_array_get(tr) < 0)
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return -ENODEV;
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iter = kzalloc(sizeof(*iter), GFP_KERNEL);
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if (!iter)
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return -ENOMEM;
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goto out;
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if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
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kfree(iter);
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return -ENOMEM;
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}
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if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
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goto out;
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iter->ops = ops;
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iter->flags = flag;
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@ -3584,13 +3585,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
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if (!iter->hash) {
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trace_parser_put(&iter->parser);
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kfree(iter);
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ret = -ENOMEM;
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goto out_unlock;
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}
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} else
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iter->hash = hash;
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ret = 0;
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if (file->f_mode & FMODE_READ) {
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iter->pg = ftrace_pages_start;
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@ -3602,7 +3603,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
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/* Failed */
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free_ftrace_hash(iter->hash);
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trace_parser_put(&iter->parser);
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kfree(iter);
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}
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} else
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file->private_data = iter;
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@ -3610,6 +3610,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
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out_unlock:
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mutex_unlock(&ops->func_hash->regex_lock);
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out:
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if (ret) {
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kfree(iter);
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if (tr)
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trace_array_put(tr);
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}
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return ret;
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}
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@ -5037,6 +5044,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
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mutex_unlock(&iter->ops->func_hash->regex_lock);
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free_ftrace_hash(iter->hash);
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if (iter->tr)
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trace_array_put(iter->tr);
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kfree(iter);
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return 0;
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