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SubjectRe: [PATCH v5 09/10] Uprobes/sdt: Document about reference counter
* Ravi Bangoria <ravi.bangoria@linux.ibm.com> [2018-06-28 10:52:08]:

> Reference counter gate the invocation of probe. If present,
> by default reference count is 0. Kernel needs to increment
> it before tracing the probe and decrement it when done. This
> is identical to semaphore in Userspace Statically Defined
> Tracepoints (USDT).
>
> Document usage of reference counter.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Unlike perf, this mechanism cannot detect ref count and depends on the
users data. What happens if the user mistakenly provides a wrong location?
I guess he can corrupt some other data structures?

Hence I would think twice of advertising this mechanism. i.e keep this
as an undocumented feature.

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