Merge tag 'perf-fixes-27504' of git://git.kernel.org/pub/scm/linux/kernel/git/tip...

Pull perf fixes from Thomas Gleixner:
 "Perf fixes for perf_mmap() reference counting to prevent potential
  reference count leaks which are caused by:

   - VMA splits, which change the offset or size of a mapping, which
     causes perf_mmap_close() to ignore the unmap or unmap the wrong
     buffer.

   - Several internal issues of perf_mmap(), which can cause reference
     count leaks in the perf mmap, corrupt accounting or cause leaks in
     perf drivers.

  The main fix is to prevent VMA splits by implementing the
  [may_]split() callback for vm operations.

  The other issues are addressed by rearranging code, early returns on
  failure and invocation of cleanups.

  Also provide a selftest to validate the fixes.

  The reference counting should be converted to refcount_t, but that
  requires larger refactoring of the code and will be done once these
  fixes are upstream"

* tag 'perf-fixes-27504' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git:
  selftests/perf_events: Add a mmap() correctness test
  perf/core: Prevent VMA split of buffer mappings
  perf/core: Handle buffer mapping fail correctly in perf_mmap()
  perf/core: Exit early on perf_mmap() fail
  perf/core: Don't leak AUX buffer refcount on allocation failure
  perf/core: Preserve AUX buffer allocation failure result