Messages in this thread |  | | Date | Wed, 18 Apr 2018 10:25:04 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/2] tracing: fix bad use of igrab in trace_uprobe.c |
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On Wed, 18 Apr 2018 16:03:42 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> > @@ -937,7 +928,8 @@ probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, > > goto err_flags; > > > > tu->consumer.filter = filter; > > - ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); > > + ret = uprobe_register(d_inode(tu->path.dentry), tu->offset, > > + &tu->consumer); > > It is not entirely clear how the lifetime of uprobe relates to the > lifetime of trace_uprobe. Is the uprobe object never going to survive > its creator trace_uprobe object?
Not exactly sure what you mean here.
The trace_uprobe (the probe event) is created, it doesn't do anything until it is enabled. This function is called when it is enabled. The trace_uprobe (probe event) can not be deleted while it is enabled (EBUSY).
Are you asking what happens if the file is deleted while it has probe? That I don't know about (haven't tried it out). But I would hope that it keeps a reference to the inode, isn't that what the igrab is for? And is now being replaced by a reference on the path, or is that the problem?
-- Steve
> > If that's the case, it warrants a comment. If that's not the case, > then the path would need to be passed to uprobe_resister() which would > need to obtain its own reference. > > > if (ret) > > goto err_buffer; > >
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