From patchwork Mon Jun 13 13:59:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lecopzer Chen X-Patchwork-Id: 12879593 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 3308BC43334 for ; Mon, 13 Jun 2022 14:02:17 +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=4FWDnNEWv2PRj6hE4EOF5i6j6JKeXeElHIIYu1EFPhc=; b=qqz7EmBaeSgdkf ChrdHSr0M1Gsm4fP01wUj/wVY4ObWLX2m75MSvKQ98nNtUzLf5BCRXQXbPhfKHWathAdBXkGKW4/L DrjUhuTxdttzYix6PW9T0kD1MhUJeIkS44mhJWqpFbLhzWWjY+4QWgTaOTUdfKGTowP2hT0h0WBPg x7moc07lVmqfeUadLl9veF9Stn4g9ycgBbtPhbNLlalcEasbYY0oaskUXd252MaLYiJMQSAsn+GVU l8GAS8e8xLAK2pDlnyIbrLZSJHAE2D3PA5beTX5cMSRzQ4tCmCgIsrN9O1WTSbHg7inf/ueIy+er/ +0FWsrLBJSrTO2jw7GUQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o0kc3-0042DH-AE; Mon, 13 Jun 2022 14:00:15 +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 1o0kc0-00429p-Ck; Mon, 13 Jun 2022 14:00:13 +0000 X-UUID: 64ea85b9b50b4be6a5a04a0dcce2bef7-20220613 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.6,REQID:dba5efbf-5eb0-4e42-8219-b5a41bbd0915,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:-5,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACT ION:release,TS:-5 X-CID-META: VersionHash:b14ad71,CLOUDID:780f69c6-12ba-4305-bfdf-9aefbdc32516,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 64ea85b9b50b4be6a5a04a0dcce2bef7-20220613 Received: from mtkcas68.mediatek.inc [(172.29.94.19)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1738113145; Mon, 13 Jun 2022 07:00:03 -0700 Received: from mtkmbs10n2.mediatek.inc (172.21.101.183) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 13 Jun 2022 07:00:01 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.3; Mon, 13 Jun 2022 22:00:00 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Mon, 13 Jun 2022 22:00:00 +0800 From: Lecopzer Chen To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v5 3/6] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event Date: Mon, 13 Jun 2022 21:59:53 +0800 Message-ID: <20220613135956.15711-4-lecopzer.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220613135956.15711-1-lecopzer.chen@mediatek.com> References: <20220613135956.15711-1-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-20220613_070012_483138_51432169 X-CRM114-Status: GOOD ( 12.47 ) 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 701f35f0e2d4..0573cef0b9dc 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -169,10 +169,16 @@ 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);