From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752800Ab1ARQSR (ORCPT ); Tue, 18 Jan 2011 11:18:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54571 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752675Ab1ARQSP (ORCPT ); Tue, 18 Jan 2011 11:18:15 -0500 Date: Tue, 18 Jan 2011 17:10:32 +0100 From: Oleg Nesterov To: Peter Zijlstra Cc: Alan Stern , Arnaldo Carvalho de Melo , Frederic Weisbecker , Ingo Molnar , Paul Mackerras , Prasad , Roland McGrath , gregkh@suse.de, linux-kernel@vger.kernel.org, stable@kernel.org Subject: [PATCH 2/2] perf: validate cpu early in perf_event_alloc() Message-ID: <20110118161032.GC693@redhat.com> References: <20101108145647.GA3426@redhat.com> <20110117203459.GA32700@redhat.com> <1295297576.30950.382.camel@laptop> <20110118160942.GA693@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110118160942.GA693@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Starting from perf_event_alloc()->perf_init_event(), the kernel assumes that event->cpu is either -1 or the valid CPU number. Change perf_event_alloc() to validate this argument early. This also means we can remove the similar check in find_get_context(). Signed-off-by: Oleg Nesterov --- kernel/perf_event.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- git/kernel/perf_event.c~2_perf_event_alloc 2011-01-18 16:56:40.000000000 +0100 +++ git/kernel/perf_event.c 2011-01-18 16:57:08.000000000 +0100 @@ -2233,9 +2233,6 @@ find_get_context(struct pmu *pmu, struct if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EACCES); - if (cpu < 0 || cpu >= nr_cpumask_bits) - return ERR_PTR(-EINVAL); - /* * We could be clever and allow to attach a event to an * offline CPU and activate it when the CPU comes up, but @@ -5541,6 +5538,11 @@ perf_event_alloc(struct perf_event_attr struct hw_perf_event *hwc; long err; + if ((unsigned)cpu >= nr_cpu_ids) { + if (!task || cpu != -1) + return ERR_PTR(-EINVAL); + } + event = kzalloc(sizeof(*event), GFP_KERNEL); if (!event) return ERR_PTR(-ENOMEM); @@ -5589,7 +5591,7 @@ perf_event_alloc(struct perf_event_attr if (!overflow_handler && parent_event) overflow_handler = parent_event->overflow_handler; - + event->overflow_handler = overflow_handler; if (attr->disabled)