Commit 339bc418 authored Mar 29, 2019 by Alexander Shishkin Committed by Ingo Molnar Apr 16, 2019

perf/ring_buffer: Fix AUX record suppression



The following commit:

  1627314f ("perf: Suppress AUX/OVERWRITE records")

has an unintended side-effect of also suppressing all AUX records with no flags
and non-zero size, so all the regular records in the full trace mode.
This breaks some use cases for people.

Fix this by restoring "regular" AUX records.

Reported-by: Ben Gainey <Ben.Gainey@arm.com>
Tested-by: Ben Gainey <Ben.Gainey@arm.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
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>
Fixes: 1627314f ("perf: Suppress AUX/OVERWRITE records")
Link: https://lkml.kernel.org/r/20190329091338.29999-1-alexander.shishkin@linux.intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 52a44f83

kernel/events/ring_buffer.c

+15 −18

Original line number	Diff line number	Diff line
		@@ -455,7 +455,6 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
		rb->aux_head += size;
		}

		if (size \|\| handle->aux_flags) {
		/*
		* Only send RECORD_AUX if we have something useful to communicate
		*
		@@ -468,11 +467,9 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
		* offset. So, from now on we don't output AUX records that
		* have only OVERWRITE flag set.
		*/

		if (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE)
		if (size \|\| (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE))
		perf_event_aux_event(handle->event, aux_head, size,
		handle->aux_flags);
		}

		rb->user_page->aux_head = rb->aux_head;
		if (rb_need_aux_wakeup(rb))