From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58194 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752604AbeDJJHU (ORCPT ); Tue, 10 Apr 2018 05:07:20 -0400 Subject: Patch "perf/core: Correct event creation with PERF_FORMAT_GROUP" has been added to the 4.4-stable tree To: peterz@infradead.org, acme@kernel.org, ak@linux.intel.com, alexander.levin@microsoft.com, alexander.shishkin@linux.intel.com, eranian@google.com, gregkh@linuxfoundation.org, jolsa@kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, vince@deater.net Cc: , From: Date: Tue, 10 Apr 2018 11:05:20 +0200 Message-ID: <152335112084242@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled perf/core: Correct event creation with PERF_FORMAT_GROUP to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-core-correct-event-creation-with-perf_format_group.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Tue Apr 10 10:31:53 CEST 2018 From: Peter Zijlstra Date: Tue, 30 May 2017 11:45:12 +0200 Subject: perf/core: Correct event creation with PERF_FORMAT_GROUP From: Peter Zijlstra [ Upstream commit ba5213ae6b88fb170c4771fef6553f759c7d8cdd ] Andi was asking about PERF_FORMAT_GROUP vs inherited events, which led to the discovery of a bug from commit: 3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff") - PERF_SAMPLE_GROUP = 1U << 4, + PERF_SAMPLE_READ = 1U << 4, - if (attr->inherit && (attr->sample_type & PERF_SAMPLE_GROUP)) + if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) is a clear fail :/ While this changes user visible behaviour; it was previously possible to create an inherited event with PERF_SAMPLE_READ; this is deemed acceptible because its results were always incorrect. Reported-by: Andi Kleen Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: 3dab77fb1bf8 ("perf: Rework/fix the whole read vs group stuff") Link: http://lkml.kernel.org/r/20170530094512.dy2nljns2uq7qa3j@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5271,9 +5271,6 @@ static void perf_output_read_one(struct __output_copy(handle, values, n * sizeof(u64)); } -/* - * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. - */ static void perf_output_read_group(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) @@ -5318,6 +5315,13 @@ static void perf_output_read_group(struc #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ PERF_FORMAT_TOTAL_TIME_RUNNING) +/* + * XXX PERF_SAMPLE_READ vs inherited events seems difficult. + * + * The problem is that its both hard and excessively expensive to iterate the + * child list, not to mention that its impossible to IPI the children running + * on another CPU, from interrupt/NMI context. + */ static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { @@ -7958,9 +7962,10 @@ perf_event_alloc(struct perf_event_attr local64_set(&hwc->period_left, hwc->sample_period); /* - * we currently do not support PERF_FORMAT_GROUP on inherited events + * We currently do not support PERF_SAMPLE_READ on inherited events. + * See perf_output_read(). */ - if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) + if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) goto err_ns; if (!has_branch_stack(event)) Patches currently in stable-queue which might be from peterz@infradead.org are queue-4.4/perf-tools-fix-copyfile_offset-update-of-output-offset.patch queue-4.4/sched-numa-use-down_read_trylock-for-the-mmap_sem.patch queue-4.4/x86-asm-don-t-use-rbp-as-a-temporary-register-in-csum_partial_copy_generic.patch queue-4.4/perf-core-correct-event-creation-with-perf_format_group.patch queue-4.4/x86-tsc-provide-tsc-unstable-boot-parameter.patch