Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759338Ab3GaI4r (ORCPT ); Wed, 31 Jul 2013 04:56:47 -0400 Received: from terminus.zytor.com ([198.137.202.10]:41739 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759185Ab3GaI4m (ORCPT ); Wed, 31 Jul 2013 04:56:42 -0400 Date: Wed, 31 Jul 2013 01:56:08 -0700 From: tip-bot for Frederic Weisbecker Message-ID: Cc: linux-kernel@vger.kernel.org, eranian@google.com, acme@redhat.com, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, namhyung@kernel.org, jolsa@redhat.com, fweisbec@gmail.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, acme@redhat.com, eranian@google.com, linux-kernel@vger.kernel.org, peterz@infradead.org, namhyung@kernel.org, jolsa@redhat.com, fweisbec@gmail.com, tglx@linutronix.de In-Reply-To: <1374539466-4799-3-git-send-email-fweisbec@gmail.com> References: <1374539466-4799-3-git-send-email-fweisbec@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Sanitize get_callchain_buffer() Git-Commit-ID: 90983b16078ab0fdc58f0dab3e8e3da79c9579a2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Wed, 31 Jul 2013 01:56:15 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4085 Lines: 136 Commit-ID: 90983b16078ab0fdc58f0dab3e8e3da79c9579a2 Gitweb: http://git.kernel.org/tip/90983b16078ab0fdc58f0dab3e8e3da79c9579a2 Author: Frederic Weisbecker AuthorDate: Tue, 23 Jul 2013 02:31:00 +0200 Committer: Ingo Molnar CommitDate: Tue, 30 Jul 2013 22:29:12 +0200 perf: Sanitize get_callchain_buffer() In case of allocation failure, get_callchain_buffer() keeps the refcount incremented for the current event. As a result, when get_callchain_buffers() returns an error, we must cleanup what it did by cancelling its last refcount with a call to put_callchain_buffers(). This is a hack in order to be able to call free_event() after that failure. The original purpose of that was to simplify the failure path. But this error handling is actually counter intuitive, ugly and not very easy to follow because one expect to see the resources used to perform a service to be cleaned by the callee if case of failure, not by the caller. So lets clean this up by cancelling the refcount from get_callchain_buffer() in case of failure. And correctly free the event accordingly in perf_event_alloc(). Signed-off-by: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Arnaldo Carvalho de Melo Cc: Stephane Eranian Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1374539466-4799-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- kernel/events/callchain.c | 2 ++ kernel/events/core.c | 41 +++++++++++++++++++++-------------------- 2 files changed, 23 insertions(+), 20 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index c772061..76a8bc5 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -117,6 +117,8 @@ int get_callchain_buffers(void) err = alloc_callchain_buffers(); exit: mutex_unlock(&callchain_mutex); + if (err) + atomic_dec(&nr_callchain_events); return err; } diff --git a/kernel/events/core.c b/kernel/events/core.c index f35aa7e..3b99862 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6457,7 +6457,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, struct pmu *pmu; struct perf_event *event; struct hw_perf_event *hwc; - long err; + long err = -EINVAL; if ((unsigned)cpu >= nr_cpu_ids) { if (!task || cpu != -1) @@ -6540,25 +6540,23 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, * we currently do not support PERF_FORMAT_GROUP on inherited events */ if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) - goto done; + goto err_ns; pmu = perf_init_event(event); - -done: - err = 0; if (!pmu) - err = -EINVAL; - else if (IS_ERR(pmu)) + goto err_ns; + else if (IS_ERR(pmu)) { err = PTR_ERR(pmu); - - if (err) { - if (event->ns) - put_pid_ns(event->ns); - kfree(event); - return ERR_PTR(err); + goto err_ns; } if (!event->parent) { + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { + err = get_callchain_buffers(); + if (err) + goto err_pmu; + } + if (event->attach_state & PERF_ATTACH_TASK) static_key_slow_inc(&perf_sched_events.key); if (event->attr.mmap || event->attr.mmap_data) @@ -6573,16 +6571,19 @@ done: atomic_inc(&per_cpu(perf_branch_stack_events, event->cpu)); } - if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { - err = get_callchain_buffers(); - if (err) { - free_event(event); - return ERR_PTR(err); - } - } } return event; + +err_pmu: + if (event->destroy) + event->destroy(event); +err_ns: + if (event->ns) + put_pid_ns(event->ns); + kfree(event); + + return ERR_PTR(err); } static int perf_copy_attr(struct perf_event_attr __user *uattr, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/