Re: [RFC PATCH 0/6] uprobes: return probe implementation

[Oleg Nesterov]

On 12/21, Anton Arapov wrote:
>
>   There are RFC uretprobes implementation. I'd be grateful for any review.

Anton, I won't look at this series till Monday (at least).

But at first glance it needs a lot of cleanups and _fixes_.

If nothing else, ->return_instances logic looks very wrong (but again,
I didn't really read this series and I already had a beer ;).

Just for example. Suppose that you insert uretprobe at exit() in glibc().
IOW, handle_swbp(rp_trampoline_vaddr) never happens. Who will cleanup
utask->return_instances and kfree() return_instance's?

Or. return_consumer_del() simply removes uprobe_consumer. Again, somehow
we should free the "pending" return_instance's. Plus we should restore
the original return adresses connected to these return_instance's. Just
suppose that uretprobe_run_handlers() is called after uprobe has gone
away. In this case ri->uprobe points to nowhere.

Oleg.

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