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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A445AC433F5 for ; Mon, 24 Jan 2022 22:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1583200AbiAXWRY (ORCPT ); Mon, 24 Jan 2022 17:17:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1580268AbiAXWJK (ORCPT ); Mon, 24 Jan 2022 17:09:10 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB6FDC0DDD8E; Mon, 24 Jan 2022 12:43:06 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 928F5B8123D; Mon, 24 Jan 2022 20:43:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE40EC340E7; Mon, 24 Jan 2022 20:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643056985; bh=Ef0aKFZYBMvVA9s3XPW/htIqwMLJc2qvSISQdGSxMoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yqUNvQ9bAirTjnOot/8y/EmcceoaDobrhzXR4KYYs9J6mcBT2q9jhO7anX1PK2jHU oTypasdsv4JMO6OgHXpgNsF92Tmr3gGIG9BtA/QGDq/Ie01+3X2n9b7MyR8vcOGJy4 syHUH7CuvVRymCPWVddmRcaSyk6JXu1RTDF6LCvY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Hari Bathini , Michael Ellerman , Sasha Levin Subject: [PATCH 5.15 647/846] powerpc: handle kdump appropriately with crash_kexec_post_notifiers option Date: Mon, 24 Jan 2022 19:42:44 +0100 Message-Id: <20220124184123.337064815@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hari Bathini [ Upstream commit 219572d2fc4135b5ce65c735d881787d48b10e71 ] Kdump can be triggered after panic_notifers since commit f06e5153f4ae2 ("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump after panic_notifers") introduced crash_kexec_post_notifiers option. But using this option would mean smp_send_stop(), that marks all other CPUs as offline, gets called before kdump is triggered. As a result, kdump routines fail to save other CPUs' registers. To fix this, kdump friendly crash_smp_send_stop() function was introduced with kernel commit 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump friendly version in panic path"). Override this kdump friendly weak function to handle crash_kexec_post_notifiers option appropriately on powerpc. Reported-by: kernel test robot Signed-off-by: Hari Bathini [Fixed signature of crash_stop_this_cpu() - reported by lkp@intel.com] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211207103719.91117-1-hbathini@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/kernel/smp.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index c7ef0739c8640..d03823aa7e4de 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -620,6 +620,36 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) } #endif +#ifdef CONFIG_NMI_IPI +static void crash_stop_this_cpu(struct pt_regs *regs) +#else +static void crash_stop_this_cpu(void *dummy) +#endif +{ + /* + * Just busy wait here and avoid marking CPU as offline to ensure + * register data is captured appropriately. + */ + while (1) + cpu_relax(); +} + +void crash_smp_send_stop(void) +{ + static bool stopped = false; + + if (stopped) + return; + + stopped = true; + +#ifdef CONFIG_NMI_IPI + smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_stop_this_cpu, 1000000); +#else + smp_call_function(crash_stop_this_cpu, NULL, 0); +#endif /* CONFIG_NMI_IPI */ +} + #ifdef CONFIG_NMI_IPI static void nmi_stop_this_cpu(struct pt_regs *regs) { -- 2.34.1