From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756315AbZKTVch (ORCPT ); Fri, 20 Nov 2009 16:32:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755651AbZKTV22 (ORCPT ); Fri, 20 Nov 2009 16:28:28 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:34627 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754762AbZKTV20 (ORCPT ); Fri, 20 Nov 2009 16:28:26 -0500 Message-Id: <20091120212509.251030114@chello.nl> References: <20091120211942.676891948@chello.nl> User-Agent: quilt/0.46-1 Date: Fri, 20 Nov 2009 22:19:56 +0100 From: Peter Zijlstra To: Paul Mackerras , Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org Subject: [PATCH 14/15] perf: fix locking for PERF_FORMAT_GROUP Content-Disposition: inline; filename=perf-time-7.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should hold event->child_mutex when iterating the inherited counters, we should hold ctx->mutex when iterating siblings. Signed-off-by: Peter Zijlstra --- kernel/perf_event.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) Index: linux-2.6/kernel/perf_event.c =================================================================== --- linux-2.6.orig/kernel/perf_event.c +++ linux-2.6/kernel/perf_event.c @@ -1782,6 +1782,7 @@ u64 perf_event_read_value(struct perf_ev *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_ev *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 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 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 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, c 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; } --