perf cpumap: Add reference count checking

Enabled when REFCNT_CHECKING is defined. The change adds a memory
allocated pointer that is interposed between the reference counted cpu
map at a get and freed by a put. The pointer replaces the original
perf_cpu_map struct, so use of the perf_cpu_map via APIs remains
unchanged. Any use of the cpu map without the API requires two versions,
handled via the RC_CHK_ACCESS macro.

This change is intended to catch:

 - use after put: using a cpumap after you have put it will cause a
   segv.
 - unbalanced puts: two puts for a get will result in a double free
   that can be captured and reported by tools like address sanitizer,
   including with the associated stack traces of allocation and frees.
 - missing puts: if a put is missing then the get turns into a memory
   leak that can be reported by leak sanitizer, including the stack
   trace at the point the get occurs.

Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexey Bayduraev <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: German Gomez <[email protected]>
Cc: Hao Luo <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Miaoqian Lin <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Riccardo Mancini <[email protected]>
Cc: Shunsuke Nakamura <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stephen Brennan <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Thomas Richter <[email protected]>,
Cc: Yury Norov <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]
[ Extracted from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions