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 6E9D1C79F9E for ; Mon, 7 Sep 2026 12:59:33 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=CJld41FLGATux1CROpwP/oYwrbdVUooAfqJNLsxMyhY=; b=gizZHu3EviqzCzj+zw55Bctso4 io2uYiwy+oGlkK5fi8X+Jle72GcXJGUcla15IOrdgAX0Ki+GluT582CfKcCkQ00LhMNCQwutuDP4I erTeD/twhLo41bJ/O2+8qaTxQnQadqLjQJn/0FGkx4cM4hLHdkF953WM/JGktY5MJ1gf3/kSVRDIB RxKncqvXcg84D4gw5oluzd3QYCV6niBZbaIv9qvyRJYF7svGoWpL9VAZGzDq1GkT5pm6ZLPblzQeC ga7YuoB7rAhXik/7AjanWD+KLvMP+LP0Q9djZADRw3nktUd/nQzU+wS4BehE3pHy6kJSTb3Nqb6zz VzzYK3oA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x3YwU-00000006sGv-1cXP; Mon, 07 Sep 2026 12:59:22 +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 1x3YwR-00000006sG3-1e9X for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2026 12:59:20 +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 7758D1476; Mon, 7 Sep 2026 05:59:13 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D4F033F7D8; Mon, 7 Sep 2026 05:59:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788785957; bh=fs6D9307+D5ofEdJVbGr/fE9RQA62x0tlXgWzmyLjRc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=u233w6RGdA63wnnNOM1ASAwHeUBU9au3b10Ya20EViUQr9/u/7lzCA0HCjc7gpO6l NEj+i2bTMvaL5FGzTDGLjpvKlyE8gThWSFwbZdk8fIdt0fARLgl6r4RJnSkSzPa/ai WUpyFueqgRTQ4D5MDkaI/ABLRrSN3tYBa86tkZXM= Message-ID: Date: Mon, 7 Sep 2026 13:59:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm_mpam: resctrl: Catch and propagate error from get_cpu_cacheinfo_id() To: Andre Przywara , James Morse Cc: Reinette Chatre , Fenghua Yu , Tony Luck , Dave Martin , Yin Li , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260902143757.3469690-1-andre.przywara@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20260902143757.3469690-1-andre.przywara@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260907_055919_473252_867E2611 X-CRM114-Status: GOOD ( 18.01 ) 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 Hi Andre, On 02/09/2026 15:37, Andre Przywara wrote: > get_cpu_cacheinfo_id() can fail, in which case it returns a negative > error value. > > Check the returned value for this error condition, before passing the > value on to other code, which would hide the negative number in some high > value in the unsigned type. > > Fixes: 36528c7681b8 ("arm_mpam: resctrl: Add support for 'MB' resource") > Signed-off-by: Andre Przywara This looks good to me. Out of interest what led you to find this? Reviewed-by: Ben Horgan Thanks, Ben > --- > drivers/resctrl/mpam_resctrl.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c > index 9d223057953ab..a5e661eff86d7 100644 > --- a/drivers/resctrl/mpam_resctrl.c > +++ b/drivers/resctrl/mpam_resctrl.c > @@ -786,7 +786,10 @@ static u32 get_mba_min(struct mpam_props *cprops) > /* Find the L3 cache that has affinity with this CPU */ > static int find_l3_equivalent_bitmask(int cpu, cpumask_var_t tmp_cpumask) > { > - u32 cache_id = get_cpu_cacheinfo_id(cpu, 3); > + int cache_id = get_cpu_cacheinfo_id(cpu, 3); > + > + if (cache_id < 0) > + return -ENOENT; > > lockdep_assert_cpus_held(); >