]> git.kernelconcepts.de Git - karo-tx-linux.git/commit
perf/core: Disable the event on a truncated AUX record
authorAlexander Shishkin <alexander.shishkin@linux.intel.com>
Tue, 10 May 2016 13:18:33 +0000 (16:18 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 19 May 2016 00:06:48 +0000 (17:06 -0700)
commite54c41be42cd77cf11817bc50f91933cda3903d9
treeeff66af1e49fcaf53b07337c97c9dde1ae215852
parent4e7e3f54cae7a6ea567c09d18c35bcc468b564c3
perf/core: Disable the event on a truncated AUX record

commit 9f448cd3cbcec8995935e60b27802ae56aac8cc0 upstream.

When the PMU driver reports a truncated AUX record, it effectively means
that there is no more usable room in the event's AUX buffer (even though
there may still be some room, so that perf_aux_output_begin() doesn't take
action). At this point the consumer still has to be woken up and the event
has to be disabled, otherwise the event will just keep spinning between
perf_aux_output_begin() and perf_aux_output_end() until its context gets
unscheduled.

Again, for cpu-wide events this means never, so once in this condition,
they will be forever losing data.

Fix this by disabling the event and waking up the consumer in case of a
truncated AUX record.

Reported-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
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: vince@deater.net
Link: http://lkml.kernel.org/r/1462886313-13660-3-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/events/ring_buffer.c