perf: Untangle 'owner' confusion
authorPeter Zijlstra <peterz@infradead.org>
Tue, 26 Jan 2016 13:55:02 +0000 (14:55 +0100)
committerIngo Molnar <mingo@kernel.org>
Fri, 29 Jan 2016 07:35:34 +0000 (08:35 +0100)
commit60beda849343494b2a598b927630bbe293c1cc6e
tree747a882487e751ae5cdcf6b0c44e013d5a9b040e
parent45a0e07abf4933490a2d2f81b1a31fe267bd3561
perf: Untangle 'owner' confusion

There are two concepts of owner wrt an event and they are conflated:

 - event::owner / event::owner_list,
   used by prctl(.option = PR_TASK_PERF_EVENTS_{EN,DIS}ABLE).

 - the 'owner' of the event object, typically the file descriptor.

Currently these two concepts are conflated, which gives trouble with
scm_rights passing of file descriptors. Passing the event and then
closing the creating task would render the event 'orphan' and would
have it cleared out. Unlikely what is expectd.

This patch untangles these two concepts by using PERF_EVENT_STATE_EXIT
to denote the second type.

Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/events/core.c