From patchwork Wed Apr 27 16:13:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lecopzer Chen X-Patchwork-Id: 12829227 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 17056C433EF for ; Wed, 27 Apr 2022 17:08:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+YL1rUmWBOahpRjOHl/RI1n8f0sbvs0WDzV+Io9zBc8=; b=aGVGAgJKULmBuY erk8oUIzRw1tUZ0aYniefbb0EsyeoucD9xMZiUiIKFGwVPKQC+H4v+yl93SvOyqvKVH8dx5DwKZ14 AtO37vEWKmDarlQ0H2FPT52gmga8HtKT5375SqtlYFDYUankf2TKziWpuWn9FHdmMkn7PvAkj87tP ul41iWkaiQPiunRt1fi4eagoUD2Pci3LZv7RDq0aIImTxnTGAagagNU5Dp44+h4Uw9vDHvm7mt/ex RPvI+k9gBcXyjxmLqsCXo+jmoeTMwAQH8iS5ODxMdJPsMFtk3G31AA1ltmeWLEu14FWzGtz5zS0P0 P2+k4i6cBZI1JSpckeJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1njl83-002Wlj-5m; Wed, 27 Apr 2022 17:07:03 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1njkOa-002GDh-7D; Wed, 27 Apr 2022 16:20:05 +0000 X-UUID: 5843e04e421d41319c20776d1f9e656b-20220427 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.4, REQID:334c022e-24c0-4270-bb51-3d2986015c6b, OB:0, LO B:0,IP:0,URL:0,TC:0,Content:-20,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,AC TION:release,TS:-20 X-CID-META: VersionHash:faefae9, CLOUDID:5964ec2e-6199-437e-8ab4-9920b4bc5b76, C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,File:nil,QS:0,BEC:nil X-UUID: 5843e04e421d41319c20776d1f9e656b-20220427 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 648742386; Wed, 27 Apr 2022 09:19:57 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 27 Apr 2022 09:13:53 -0700 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Thu, 28 Apr 2022 00:13:51 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 28 Apr 2022 00:13:51 +0800 From: Lecopzer Chen To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v4 3/6] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event Date: Thu, 28 Apr 2022 00:13:37 +0800 Message-ID: <20220427161340.8518-4-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220427161340.8518-1-lecopzer.chen@mediatek.com> References: <20220427161340.8518-1-lecopzer.chen@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220427_092004_380414_9EDE3C31 X-CRM114-Status: GOOD ( 12.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Pingfan Liu hardlockup_detector_event_create() should create perf_event on the current CPU. Preemption could not get disabled because perf_event_create_kernel_counter() allocates memory. Instead, the CPU locality is achieved by processing the code in a per-CPU bound kthread. Add a check to prevent mistakes when calling the code in another code path. Signed-off-by: Pingfan Liu Co-developed-by: Lecopzer Chen Signed-off-by: Lecopzer Chen Reviewed-by: Petr Mladek --- kernel/watchdog_hld.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 247bf0b1582c..96b717205952 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -165,10 +165,16 @@ static void watchdog_overflow_callback(struct perf_event *event, static int hardlockup_detector_event_create(void) { - unsigned int cpu = smp_processor_id(); + unsigned int cpu; struct perf_event_attr *wd_attr; struct perf_event *evt; + /* + * Preemption is not disabled because memory will be allocated. + * Ensure CPU-locality by calling this in per-CPU kthread. + */ + WARN_ON(!is_percpu_thread()); + cpu = raw_smp_processor_id(); wd_attr = &wd_hw_attr; wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);