From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49REWiVR1Mg0wC0TwHQpOaYSgNIkcqpCOIXqdRviYJ96N1HKXQMoGVwbM1bDOMBGTfh4Ssq ARC-Seal: i=1; a=rsa-sha256; t=1523472564; cv=none; d=google.com; s=arc-20160816; b=MRWVbVRnN7urJqNST0JgZgRttNAVIdqVYc/D62GDplvGJI+SqjOhleokRTFseAYaGm kkYHYKO4KNLoLZWHYEEhvRnfvkfZHs8H027WpepE++aJ9QXj7a9HsrWcs6UMQMVTkHsG 35Kmc12T2tgsSLyZdpE5tcRLxZBf8K6OWDMNROYyU2yuufJJ+J+eAjufWhaK8e3GEhmT OE1k2wXYm0ZiBGwLzR2LrneNXyRuweNbKy5EJ6nq0jeJL55P2IeLT3RV4cxsHPknMuR2 OnjkyxdfH4vWqnGg1pIG+35tRx3BNOkdBXrGv/m53kHLktOAugUluciM+9iyZA87W26W Gtag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=BbM9hsqOcwRylpDwPAHAysKPUMneK03aaGkEI0TAGDA=; b=IvW2SSrdCRROoHv+YRazzapexD5Y4WgsXDJcJy1z830u8zgoWwj6w0GOYt+8LlasWU wwFQeV40zF8tBH4Q0z/Ds4xCo6R3pULbLp+FUuDeOGXgstD+tEuNfHnfi1DUmF6BppqI zgVlNr+g+pNGnXqxBDOKYWGTS96QfZh4rCQD7rb7F4qMVJtdicwXx5+d2GUJ8XEOE20b o8X9PwbibHPDk1BVAR2ujf5rifp02B9BuREbrvwN7PTAFPaPQzweLxOL4ojZHnTHZa2s Dh2F6HpOp94Fw2KEV2TZpRJS/I5/2AEX3YHIjhvDXQjM3dVOVTbr41DRYX33MfLQbZkW jKuA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andi Kleen , "Peter Zijlstra (Intel)" , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Vince Weaver , Ingo Molnar , Sasha Levin Subject: [PATCH 4.4 130/190] perf/core: Correct event creation with PERF_FORMAT_GROUP Date: Wed, 11 Apr 2018 20:36:16 +0200 Message-Id: <20180411183559.831292963@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180411183550.114495991@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597476252641342543?= X-GMAIL-MSGID: =?utf-8?q?1597476767874004704?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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))