Re: [PATCH 0/9] tools subsystem refcounter conversions

[Peter Zijlstra]

On Tue, Feb 21, 2017 at 05:34:54PM +0200, Elena Reshetova wrote:
> Now when new refcount_t type and API are finally merged
> (see include/linux/refcount.h), the following
> patches convert various refcounters in the tools susystem from atomic_t
> to refcount_t. By doing this we prevent intentional or accidental
> underflows or overflows that can led to use-after-free vulnerabilities.
> 
> The below patches are fully independent and can be cherry-picked separately.
> Since we convert all kernel subsystems in the same fashion, resulting
> in about 300 patches, we have to group them for sending at least in some
> fashion to be manageable. Please excuse the long cc list.
> 
> Elena Reshetova (9):
>   tools: convert cgroup_sel.refcnt from atomic_t to refcount_t
>   tools: convert cpu_map.refcnt from atomic_t to refcount_t
>   tools: convert comm_str.refcnt from atomic_t to refcount_t
>   tools: convert dso.refcnt from atomic_t to refcount_t
>   tools: convert map.refcnt from atomic_t to refcount_t
>   tools: convert map_groups.refcnt from atomic_t to refcount_t
>   tools: convert perf_map.refcnt from atomic_t to refcount_t
>   tools: convert thread.refcnt from atomic_t to refcount_t
>   tools: convert thread_map.refcnt from atomic_t to refcount_t
> 
>  tools/perf/util/cgroup.c     |  6 +++---
>  tools/perf/util/cgroup.h     |  4 ++--
>  tools/perf/util/comm.c       | 13 +++++--------
>  tools/perf/util/cpumap.c     | 16 ++++++++--------
>  tools/perf/util/cpumap.h     |  4 ++--
>  tools/perf/util/dso.c        |  6 +++---
>  tools/perf/util/dso.h        |  4 ++--
>  tools/perf/util/evlist.c     | 18 +++++++++---------
>  tools/perf/util/evlist.h     |  4 ++--
>  tools/perf/util/map.c        | 10 +++++-----
>  tools/perf/util/map.h        | 10 +++++-----
>  tools/perf/util/thread.c     |  6 +++---
>  tools/perf/util/thread.h     |  4 ++--
>  tools/perf/util/thread_map.c | 20 ++++++++++----------
>  tools/perf/util/thread_map.h |  4 ++--

This is userspace code; did you build this? I see a distinct lack of
adding refcount.h to the userspace headers.