- On Mar 8, 2017, at 11:38 AM, Francis Deslauriers
francis.deslauri...@efficios.com wrote:
> The previous implementation assumed that `atomic_add_unless` returned the
> prior value of the atomic counter when in fact it returned if addition was
> successful(true) or overflowed(false).
I think you mean "if addition was performed (true) or not performed (false)" ?
Thanks,
Mathieu
> Since `atomic_add_unless` can not return INT_MAX, the `lttng_kref_get`
> always returned that the call was successful.
>
> This issue had a low likelihood of being triggered since the two refcounts
> of the counters used with this call are both bounded by the maximum
> number of file descriptors on the system.
>
> Signed-off-by: Francis Deslauriers
> ---
> wrapper/kref.h | 6 +-
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/wrapper/kref.h b/wrapper/kref.h
> index eedefbf..f30a9ae 100644
> --- a/wrapper/kref.h
> +++ b/wrapper/kref.h
> @@ -36,11 +36,7 @@
> */
> static inline int lttng_kref_get(struct kref *kref)
> {
> - if (atomic_add_unless(&kref->refcount, 1, INT_MAX) != INT_MAX) {
> - return 1;
> - } else {
> - return 0;
> - }
> + return atomic_add_unless(&kref->refcount, 1, INT_MAX);
> }
>
> #endif /* _LTTNG_WRAPPER_KREF_H */
> --
> 2.7.4
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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