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SubjectRe: [PATCH v5 06/10] Uprobes: Support SDT markers having reference count (semaphore)
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Hi Song,

On 07/14/2018 05:20 AM, Song Liu wrote:
>
> Hmm... what happens when we have multiple uprobes sharing the same
> reference counter? It feels equally complicate to me. Or did I miss any
> cases here?


As far as I can think of, it should be handled by default. No special
treatment needed for this.

...

>
> This patch tries to resolve this imbalance by passing extra flag
> "restore_insn" to probe_event_disable().
>
> Signed-off-by: Song Liu <songliubraving@fb.com>


Ah cool. Seems this will make them balanced. But is it fine to change
uprobe_unregister()? It's already an ABI. No other way around?

Also, one more source of imbalance is this condition:

if (is_register)
flags |= VM_WRITE;

in valid_vma(). You need to take care of that as well.

Thanks,
Ravi

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