From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755342AbZKUNoe (ORCPT ); Sat, 21 Nov 2009 08:44:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755312AbZKUNoc (ORCPT ); Sat, 21 Nov 2009 08:44:32 -0500 Received: from hera.kernel.org ([140.211.167.34]:32780 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755205AbZKUNo2 (ORCPT ); Sat, 21 Nov 2009 08:44:28 -0500 Date: Sat, 21 Nov 2009 13:44:00 GMT From: tip-bot for Peter Zijlstra Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091120212509.251030114@chello.nl> References: <20091120212509.251030114@chello.nl> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Fix locking for PERF_FORMAT_GROUP Message-ID: Git-Commit-ID: 6f10581aeaa5543a3b7a8c7a87a064375ec357f8 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6f10581aeaa5543a3b7a8c7a87a064375ec357f8 Gitweb: http://git.kernel.org/tip/6f10581aeaa5543a3b7a8c7a87a064375ec357f8 Author: Peter Zijlstra AuthorDate: Fri, 20 Nov 2009 22:19:56 +0100 Committer: Ingo Molnar CommitDate: Sat, 21 Nov 2009 14:11:40 +0100 perf: Fix locking for PERF_FORMAT_GROUP We should hold event->child_mutex when iterating the inherited counters, we should hold ctx->mutex when iterating siblings. Signed-off-by: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <20091120212509.251030114@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 20 +++++++++++++------- 1 files changed, 13 insertions(+), 7 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 80f40da..3ede098 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1782,6 +1782,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) *enabled = 0; *running = 0; + mutex_lock(&event->child_mutex); total += perf_event_read(event); *enabled += event->total_time_enabled + atomic64_read(&event->child_total_time_enabled); @@ -1793,6 +1794,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) *enabled += child->total_time_enabled; *running += child->total_time_running; } + mutex_unlock(&event->child_mutex); return total; } @@ -1802,10 +1804,12 @@ static int perf_event_read_group(struct perf_event *event, u64 read_format, char __user *buf) { struct perf_event *leader = event->group_leader, *sub; - int n = 0, size = 0, ret = 0; + int n = 0, size = 0, ret = -EFAULT; + struct perf_event_context *ctx = leader->ctx; u64 values[5]; u64 count, enabled, running; + mutex_lock(&ctx->mutex); count = perf_event_read_value(leader, &enabled, &running); values[n++] = 1 + leader->nr_siblings; @@ -1820,9 +1824,9 @@ static int perf_event_read_group(struct perf_event *event, size = n * sizeof(u64); if (copy_to_user(buf, values, size)) - return -EFAULT; + goto unlock; - ret += size; + ret = size; list_for_each_entry(sub, &leader->sibling_list, group_entry) { n = 0; @@ -1833,11 +1837,15 @@ static int perf_event_read_group(struct perf_event *event, size = n * sizeof(u64); - if (copy_to_user(buf + size, values, size)) - return -EFAULT; + if (copy_to_user(buf + size, values, size)) { + ret = -EFAULT; + goto unlock; + } ret += size; } +unlock: + mutex_unlock(&ctx->mutex); return ret; } @@ -1884,12 +1892,10 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) return -ENOSPC; WARN_ON_ONCE(event->ctx->parent_ctx); - mutex_lock(&event->child_mutex); if (read_format & PERF_FORMAT_GROUP) ret = perf_event_read_group(event, read_format, buf); else ret = perf_event_read_one(event, read_format, buf); - mutex_unlock(&event->child_mutex); return ret; }