From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751172AbdHVP7b (ORCPT ); Tue, 22 Aug 2017 11:59:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48550 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751010AbdHVP7a (ORCPT ); Tue, 22 Aug 2017 11:59:30 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com E6E7668CB Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=oleg@redhat.com Date: Tue, 22 Aug 2017 17:59:28 +0200 From: Oleg Nesterov To: Peter Zijlstra Cc: Arnaldo Carvalho , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH] perf_event_pid: don't report zero pids for exiting tasks Message-ID: <20170822155928.GA6892@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 22 Aug 2017 15:59:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The exiting/dead task has no pids and in this case perf_event_pid/tid return zero, change them to return -1 to distinguish this case from idle threads. Signed-off-by: Oleg Nesterov --- kernel/events/core.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 426c2ff..8c597d4 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1249,26 +1249,31 @@ unclone_ctx(struct perf_event_context *ctx) return parent_ctx; } -static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) +static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, + enum pid_type type) { + u32 nr; /* * only top level events have the pid namespace they were created in */ if (event->parent) event = event->parent; - return task_tgid_nr_ns(p, event->ns); + nr = __task_pid_nr_ns(p, type, event->ns); + /* avoid -1 if it is idle thread or runs in another ns */ + if (!nr && !pid_alive(p)) + nr = -1; + return nr; } -static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) { - /* - * only top level events have the pid namespace they were created in - */ - if (event->parent) - event = event->parent; + return perf_event_pid_type(event, p, __PIDTYPE_TGID); +} - return task_pid_nr_ns(p, event->ns); +static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +{ + return perf_event_pid_type(event, p, PIDTYPE_PID); } /* -- 2.5.0