From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760752AbZCYMHu (ORCPT ); Wed, 25 Mar 2009 08:07:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760371AbZCYMHa (ORCPT ); Wed, 25 Mar 2009 08:07:30 -0400 Received: from hera.kernel.org ([140.211.167.34]:57117 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760296AbZCYMH2 (ORCPT ); Wed, 25 Mar 2009 08:07:28 -0400 Date: Wed, 25 Mar 2009 12:06:45 GMT From: Peter Zijlstra To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, efault@gmx.de, arjan@infradead.org, tglx@linutronix.de, fengguang.wu@intel.com, mingo@elte.hu Reply-To: arjan@infradead.org, mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, fengguang.wu@intel.com, mingo@elte.hu In-Reply-To: <20090325113316.921433024@chello.nl> References: <20090325113316.921433024@chello.nl> Subject: [tip:perfcounters/core] perf_counter: sanity check on the output API Message-ID: Git-Commit-ID: 91d876bd14c82826b69bf23f502cb283959ebb1f X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Wed, 25 Mar 2009 12:06:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 91d876bd14c82826b69bf23f502cb283959ebb1f Gitweb: http://git.kernel.org/tip/91d876bd14c82826b69bf23f502cb283959ebb1f Author: Peter Zijlstra AuthorDate: Wed, 25 Mar 2009 12:30:24 +0100 Committer: Ingo Molnar CommitDate: Wed, 25 Mar 2009 13:02:52 +0100 perf_counter: sanity check on the output API Ensure we never write more than we said we would. Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Mike Galbraith Cc: Arjan van de Ven Cc: Wu Fengguang LKML-Reference: <20090325113316.921433024@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index d76e311..7669afe 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1422,6 +1422,7 @@ struct perf_output_handle { struct perf_counter *counter; struct perf_mmap_data *data; unsigned int offset; + unsigned int head; int wakeup; }; @@ -1447,6 +1448,7 @@ static int perf_output_begin(struct perf_output_handle *handle, handle->counter = counter; handle->data = data; handle->offset = offset; + handle->head = head; handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT); return 0; @@ -1485,6 +1487,8 @@ static void perf_output_copy(struct perf_output_handle *handle, } while (len); handle->offset = offset; + + WARN_ON_ONCE(handle->offset > handle->head); } #define perf_output_put(handle, x) \