perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data
authorPeter Zijlstra <peterz@infradead.org>
Fri, 17 May 2019 11:52:33 +0000 (13:52 +0200)
committerIngo Molnar <mingo@kernel.org>
Fri, 24 May 2019 07:00:11 +0000 (09:00 +0200)
commit4d839dd9e4356bbacf3eb0ab13a549b83b008c21
tree292041201ff781e82df44f9f6a5a60654c8f2ebe
parent3f9fbe9bd86c534eba2faf5d840fd44c6049f50e
perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data

We must use {READ,WRITE}_ONCE() on rb->user_page data such that
concurrent usage will see whole values. A few key sites were missing
this.

Suggested-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.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>
Cc: acme@kernel.org
Cc: mark.rutland@arm.com
Cc: namhyung@kernel.org
Fixes: 7b732a750477 ("perf_counter: new output ABI - part 1")
Link: http://lkml.kernel.org/r/20190517115418.394192145@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/events/ring_buffer.c