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SubjectRe: [PATCH 1/2] tracing: fix bad use of igrab in trace_uprobe.c
On Wed, 18 Apr 2018 16:03:42 +0200
Miklos Szeredi <> 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

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

-- 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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