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 CC23ECA5FDD for ; Fri, 2 Oct 2026 17:40:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=x84MT/H+0RiUwiZgP2LT8qCjYkeU95gapw/4pD6Pkr4=; b=H8kVrHTHDGm9IrtUEqCVQzZKSe vHSxXhjKJC3JkPmQYLp4yDMjsOKRHkL6Toi1luVyQzv44z2Xc19YPMPW/NMrGJVSxxgbO9dGqvVLa VxoLR0Kdlu7Tp3esm3JtnfrICXkvYXrErnrbx+SvJmHc++V4zZxhhnLDYpEtbc81Lo3Klb9e2jIIT wV5ItrRIpncLTJVLNS3HHS1g20FlK47X1x0jpaYVQWSPdhGzhIM0e4DZEXz9BzT+Om6JC7clwOQv/ 1SFFfbri4Dd8V270jOR75in97F0iLk9q5fZXEfBHp8Nx8+7fe3/+nQiD7bwLVQTf3+oU/KytswCHg iJ8gyIrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xChF5-0000000CBWP-3lqs; Fri, 02 Oct 2026 17:40:19 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xChF0-0000000CBME-3KBF for linux-arm-kernel@lists.infradead.org; Fri, 02 Oct 2026 17:40:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 67AB8143D; Fri, 2 Oct 2026 10:40:10 -0700 (PDT) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.2.212.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BD4683F85F; Fri, 2 Oct 2026 10:40:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790962813; bh=jiUcB6Ia70sGz40GpXsNl4VxyMwTd56HDrRJrxLENOk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tQ5bxWeosuPVJi80jF8O6e4Uq3NBSx0Qzs6f/7mvHbJFV2FM5Kx253RGAuNQvKR4n m1Zel7U82ASQoQ4u53shT7piU7VqPTrIJvjY15P+S7D9So8mv7E/PXR0T9wnXnVM7p D+5zcIFwb2M/jFADAAhNDwPEqKFNpR3OrgN6hPXs= From: James Morse To: linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Ben Horgan , Andre Przywara , Fuad Tabba , Gavin Shan , James Morse Subject: [PATCH 10/27] arm_mpam: Don't loop forever if there is the maximum possible amount of PARTIDs Date: Fri, 2 Oct 2026 18:39:23 +0100 Message-ID: <20261002173941.292319-11-james.morse@arm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261002173941.292319-1-james.morse@arm.com> References: <20261002173941.292319-1-james.morse@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261002_104014_880660_5619AC0C X-CRM114-Status: GOOD ( 12.08 ) 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: Ben Horgan On a theoretical platform with the maximum possible number of usable PARTIDs, 0XFFFF, the loops iterating over PARTID in mpam_reset_ris() and mpam_reprogram_ris() will never reach their termination condition leading to a system hang when register the cpu hotplug handlers when MPAM is enabling. Fix these loops. Fixes: f188a36ca241 ("arm_mpam: Reset MSC controls from cpuhp callbacks") Fixes: 09b89d2a72f3 ("arm_mpam: Allow configuration to be applied and restored during cpu online") Signed-off-by: Ben Horgan Tested-by: Gavin Shan Reviewed-by: Gavin Shan Reviewed-by: James Morse Signed-off-by: James Morse --- drivers/resctrl/mpam_devices.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 2369f814de48..67545df984fa 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -1760,7 +1760,7 @@ static int mpam_save_mbwu_state(void *arg) */ static int mpam_reset_ris(void *arg) { - u16 partid, partid_max; + u16 partid_max; struct mpam_config reset_cfg = {}; struct mpam_msc_ris *ris = arg; @@ -1770,7 +1770,7 @@ static int mpam_reset_ris(void *arg) spin_lock(&partid_max_lock); partid_max = mpam_partid_max; spin_unlock(&partid_max_lock); - for (partid = 0; partid <= partid_max; partid++) + for (u32 partid = 0; partid <= partid_max; partid++) mpam_reprogram_ris_partid(ris, partid, &reset_cfg); return 0; @@ -1817,7 +1817,6 @@ static int __write_config(void *arg) static void mpam_reprogram_msc(struct mpam_msc *msc) { - u16 partid; bool reset; struct mpam_config *cfg; struct mpam_msc_ris *ris; @@ -1841,7 +1840,7 @@ static void mpam_reprogram_msc(struct mpam_msc *msc) arg.comp = ris->vmsc->comp; arg.ris = ris; reset = true; - for (partid = 0; partid <= mpam_partid_max; partid++) { + for (u32 partid = 0; partid <= mpam_partid_max; partid++) { cfg = &ris->vmsc->comp->cfg[partid]; if (!bitmap_empty(cfg->features, MPAM_FEATURE_LAST)) reset = false; -- 2.53.0