From patchwork Tue Jan 22 07:39:52 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 2016671 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 4E10A3FCDE for ; Tue, 22 Jan 2013 07:51:21 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TxYb7-0002g1-WD; Tue, 22 Jan 2013 07:48:46 +0000 Received: from e23smtp03.au.ibm.com ([202.81.31.145]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TxYUY-0005cw-CJ for linux-arm-kernel@lists.infradead.org; Tue, 22 Jan 2013 07:41:59 +0000 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 22 Jan 2013 17:36:43 +1000 Received: from d23dlp01.au.ibm.com (202.81.31.203) by e23smtp03.au.ibm.com (202.81.31.209) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 22 Jan 2013 17:36:40 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id D352F2CE804F for ; Tue, 22 Jan 2013 18:41:50 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0M7Turf63373334 for ; Tue, 22 Jan 2013 18:29:56 +1100 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0M7fmP7014312 for ; Tue, 22 Jan 2013 18:41:49 +1100 Received: from srivatsabhat.in.ibm.com (srivatsabhat.in.ibm.com [9.124.35.112]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r0M7fbE8014060; Tue, 22 Jan 2013 18:41:38 +1100 From: "Srivatsa S. Bhat" Subject: [PATCH v5 26/45] perf/x86: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org Date: Tue, 22 Jan 2013 13:09:52 +0530 Message-ID: <20130122073948.13822.43399.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012207-6102-0000-0000-000002E62BCF X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130122_024158_937038_E8AC1D33 X-CRM114-Status: GOOD ( 13.46 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [202.81.31.145 listed in list.dnswl.org] 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-arch@vger.kernel.org, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, wangyun@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The CPU_DYING notifier modifies the per-cpu pointer pmu->box, and this can race with functions such as uncore_pmu_to_box() and uncore_pci_remove() when we remove stop_machine() from the CPU offline path. So protect them using get/put_online_cpus_atomic(). Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Arnaldo Carvalho de Melo Signed-off-by: Srivatsa S. Bhat --- arch/x86/kernel/cpu/perf_event_intel_uncore.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c index b43200d..6faae53 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c @@ -1,3 +1,4 @@ +#include #include "perf_event_intel_uncore.h" static struct intel_uncore_type *empty_uncore[] = { NULL, }; @@ -1965,6 +1966,7 @@ uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu) if (box) return box; + get_online_cpus_atomic(); raw_spin_lock(&uncore_box_lock); list_for_each_entry(box, &pmu->box_list, list) { if (box->phys_id == topology_physical_package_id(cpu)) { @@ -1974,6 +1976,7 @@ uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu) } } raw_spin_unlock(&uncore_box_lock); + put_online_cpus_atomic(); return *per_cpu_ptr(pmu->box, cpu); } @@ -2556,6 +2559,7 @@ static void uncore_pci_remove(struct pci_dev *pdev) if (WARN_ON_ONCE(phys_id != box->phys_id)) return; + get_online_cpus_atomic(); raw_spin_lock(&uncore_box_lock); list_del(&box->list); raw_spin_unlock(&uncore_box_lock); @@ -2569,6 +2573,7 @@ static void uncore_pci_remove(struct pci_dev *pdev) WARN_ON_ONCE(atomic_read(&box->refcnt) != 1); kfree(box); + put_online_cpus_atomic(); } static int uncore_pci_probe(struct pci_dev *pdev,