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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C0E3C282C3 for ; Thu, 24 Jan 2019 19:42:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57814218D9 for ; Thu, 24 Jan 2019 19:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548358964; bh=+OTlQXf2WPDqQDpfcmOcYhokNvO14YPsmgZoCmDVWgM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Kuvw0Bt56+mdxCVGfM+f9CgwqP2mYfKvL62W3+DcnC3D/F7oHRaK+e9qaDEReWdfG WqkmkAbrzOlOZLBD1J0m+14Bg/kZ4G0utr0SeroD1A6pizGB8sDZSz0QRGZQPVuDpX QmC/oIP+VH9/a9nePEjDICDrJruEIWtyY3As5tWM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387826AbfAXTmm (ORCPT ); Thu, 24 Jan 2019 14:42:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:40778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733252AbfAXTkh (ORCPT ); Thu, 24 Jan 2019 14:40:37 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D004C218F0; Thu, 24 Jan 2019 19:40:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548358836; bh=+OTlQXf2WPDqQDpfcmOcYhokNvO14YPsmgZoCmDVWgM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Jn8UpWZf53WRIGYB5zorBOc81Lvf9ngXrLlhmxZqKyQ7P2KNlO9yXpgexnUg2y8A5 P92gAFSkU3GNB7/MfFkQ2B7QFFALtLblVLTp4HSwX1NSWLyV5QguuLZwSLz1MaCzV8 wHquPD+z2xbPoY3GBP6zuAOIeQmrXWGmIg0j3vhc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Morse , Will Deacon , Sasha Levin Subject: [PATCH 4.20 044/127] arm64: Use a raw spinlock in __install_bp_hardening_cb() Date: Thu, 24 Jan 2019 20:19:50 +0100 Message-Id: <20190124190214.134552997@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190124190211.984305387@linuxfoundation.org> References: <20190124190211.984305387@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit d8797b125711f23d83f5a71e908d34dfcd1fc3e9 ] __install_bp_hardening_cb() is called via stop_machine() as part of the cpu_enable callback. To force each CPU to take its turn when allocating slots, they take a spinlock. With the RT patches applied, the spinlock becomes a mutex, and we get warnings about sleeping while in stop_machine(): | [ 0.319176] CPU features: detected: RAS Extension Support | [ 0.319950] BUG: scheduling while atomic: migration/3/36/0x00000002 | [ 0.319955] Modules linked in: | [ 0.319958] Preemption disabled at: | [ 0.319969] [] cpu_stopper_thread+0x7c/0x108 | [ 0.319973] CPU: 3 PID: 36 Comm: migration/3 Not tainted 4.19.1-rt3-00250-g330fc2c2a880 #2 | [ 0.319975] Hardware name: linux,dummy-virt (DT) | [ 0.319976] Call trace: | [ 0.319981] dump_backtrace+0x0/0x148 | [ 0.319983] show_stack+0x14/0x20 | [ 0.319987] dump_stack+0x80/0xa4 | [ 0.319989] __schedule_bug+0x94/0xb0 | [ 0.319991] __schedule+0x510/0x560 | [ 0.319992] schedule+0x38/0xe8 | [ 0.319994] rt_spin_lock_slowlock_locked+0xf0/0x278 | [ 0.319996] rt_spin_lock_slowlock+0x5c/0x90 | [ 0.319998] rt_spin_lock+0x54/0x58 | [ 0.320000] enable_smccc_arch_workaround_1+0xdc/0x260 | [ 0.320001] __enable_cpu_capability+0x10/0x20 | [ 0.320003] multi_cpu_stop+0x84/0x108 | [ 0.320004] cpu_stopper_thread+0x84/0x108 | [ 0.320008] smpboot_thread_fn+0x1e8/0x2b0 | [ 0.320009] kthread+0x124/0x128 | [ 0.320010] ret_from_fork+0x10/0x18 Switch this to a raw spinlock, as we know this is only called with IRQs masked. Signed-off-by: James Morse Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/cpu_errata.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 6ad715d67df8..99622e5ad21b 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -135,7 +135,7 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, const char *hyp_vecs_end) { - static DEFINE_SPINLOCK(bp_lock); + static DEFINE_RAW_SPINLOCK(bp_lock); int cpu, slot = -1; /* @@ -147,7 +147,7 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, return; } - spin_lock(&bp_lock); + raw_spin_lock(&bp_lock); for_each_possible_cpu(cpu) { if (per_cpu(bp_hardening_data.fn, cpu) == fn) { slot = per_cpu(bp_hardening_data.hyp_vectors_slot, cpu); @@ -163,7 +163,7 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, __this_cpu_write(bp_hardening_data.hyp_vectors_slot, slot); __this_cpu_write(bp_hardening_data.fn, fn); - spin_unlock(&bp_lock); + raw_spin_unlock(&bp_lock); } #else #define __smccc_workaround_1_smc_start NULL -- 2.19.1