From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934240AbaFIXFh (ORCPT ); Mon, 9 Jun 2014 19:05:37 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56799 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933769AbaFIWpl (ORCPT ); Mon, 9 Jun 2014 18:45:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vince Weaver , Peter Zijlstra , Thomas Gleixner Subject: [PATCH 3.10 04/40] perf: Limit perf_event_attr::sample_period to 63 bits Date: Mon, 9 Jun 2014 15:48:35 -0700 Message-Id: <20140609224839.356006219@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140609224839.127615063@linuxfoundation.org> References: <20140609224839.127615063@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 0819b2e30ccb93edf04876237b6205eef84ec8d2 upstream. Vince reported that using a large sample_period (one with bit 63 set) results in wreckage since while the sample_period is fundamentally unsigned (negative periods don't make sense) the way we implement things very much rely on signed logic. So limit sample_period to 63 bits to avoid tripping over this. Reported-by: Vince Weaver Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6590,6 +6590,9 @@ SYSCALL_DEFINE5(perf_event_open, if (attr.freq) { if (attr.sample_freq > sysctl_perf_event_sample_rate) return -EINVAL; + } else { + if (attr.sample_period & (1ULL << 63)) + return -EINVAL; } /*