From mboxrd@z Thu Jan 1 00:00:00 1970 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 F23FDC4167B for ; Tue, 28 Nov 2023 14:41:19 +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:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=hWgr4O4W2K9PSyzJpByANtdky+40HLR0U+TjFRv2okU=; b=4UpwAnzatxgSv8 vX83bNS/0khPKBmZLJ6wdLJ9rZN3RbUJBRSG/UK+vd5ql0SdO8LhwzdOYZoQCuHs7E5o6ccSLmBCq 46fWJSru1LviRhJ3jBSf2Z5+MXppK0Ep5pzMmRSXQyaWdczzDFW2Z9pqohACAEZ4/+PKYNATo/iK4 Q5g+SHC/60j4YVvPNYfC1MTzMlc/1QLmVyYg3bs15L0fdE9PHO/Y6GmB4GwpZx5DI8Idu/GirlT6L p5z04PkfxZGWgw0QOS8UVqa8fbkQO+h2V9zYiilWMKvUBRfyhrO28aOdZZuofaMJ4CiXSFcmkh1Pb i2mO6CrO3yu8unkTs4FQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r7zGz-005WrS-0X; Tue, 28 Nov 2023 14:41:13 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1r7zGu-005Woz-2b; Tue, 28 Nov 2023 14:41:10 +0000 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4SflQ45R4nz6J6v1; Tue, 28 Nov 2023 22:36:28 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id E3876140682; Tue, 28 Nov 2023 22:41:00 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 28 Nov 2023 14:41:00 +0000 Date: Tue, 28 Nov 2023 14:40:59 +0000 From: Jonathan Cameron To: Russell King CC: , , , , , , , , , , , , , Salil Mehta , Jean-Philippe Brucker , , , James Morse , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: Re: [PATCH RFC 02/22] x86: intel_epb: Don't rely on link order Message-ID: <20231128144059.000042c8@Huawei.com> In-Reply-To: References: Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231128_064108_988374_D0DC884E X-CRM114-Status: GOOD ( 16.00 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, 07 Nov 2023 10:29:28 +0000 Russell King wrote: > From: James Morse > > intel_epb_init() is called as a subsys_initcall() to register cpuhp > callbacks. The callbacks make use of get_cpu_device() which will return > NULL unless register_cpu() has been called. register_cpu() is called > from topology_init(), which is also a subsys_initcall(). > > This is fragile. Moving the register_cpu() to a different > subsys_initcall() leads to a NULL dereference during boot. > > Make intel_epb_init() a late_initcall(), user-space can't provide a > policy before this point anyway. > > Signed-off-by: James Morse > Signed-off-by: Russell King (Oracle) Seems reasonable. FWIW Reviewed-by: Jonathan Cameron > --- > subsys_initcall_sync() would be an option, but moving the register_cpu() > calls into ACPI also means adding a safety net for CPUs that are online > but not described properly by firmware. This lives in subsys_initcall_sync(). > --- > arch/x86/kernel/cpu/intel_epb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/cpu/intel_epb.c b/arch/x86/kernel/cpu/intel_epb.c > index e4c3ba91321c..f18d35fe27a9 100644 > --- a/arch/x86/kernel/cpu/intel_epb.c > +++ b/arch/x86/kernel/cpu/intel_epb.c > @@ -237,4 +237,4 @@ static __init int intel_epb_init(void) > cpuhp_remove_state(CPUHP_AP_X86_INTEL_EPB_ONLINE); > return ret; > } > -subsys_initcall(intel_epb_init); > +late_initcall(intel_epb_init); _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv