From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx01.omp.ru (mx01.omp.ru [90.154.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 969B03B791 for ; Mon, 9 Sep 2024 19:23:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.154.21.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725909814; cv=none; b=TmXb1RyePiwA8ob+LKKiqGLw/y0YI26tbCvIVo//naabd6XH6ZhU+hU+rxxI2lFh5YQTchZTGHUO1cotxW/QF81bnEOT7gL8sXPx1Y6oYNANGEgUZ+oTykin14xEbIJIygNjOOAng2KfXKNEo5+lTLI1pt4Px3NO80I1qfmOFjs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725909814; c=relaxed/simple; bh=WxYA18Z9ULzrNShVdG9IgXbo4QUfxmI5AbCPKxUpit8=; h=Subject:To:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=DJ1qubapscAcWvB6no5uZeyay0NX1pIGWnANOzPGggOe7ZxNRlBkncFWBm6pnOnzhyg1FqbV9zsLLhJdE8pnNt/9JS4cMjt3O+WUM4GuJjlQ9ImCNEHTaMP+Xq4ZJV/O4pSBCB2kEIH4q21SGytoH9iuIUVn3FR+p/Gt6bmKbCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=omp.ru; spf=pass smtp.mailfrom=omp.ru; arc=none smtp.client-ip=90.154.21.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=omp.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=omp.ru Received: from [192.168.1.106] (31.173.81.96) by msexch01.omp.ru (10.188.4.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1258.12; Mon, 9 Sep 2024 22:23:22 +0300 Subject: Re: [PATCH] irqchip/gic: prevent buffer overflow in gic_ipi_send_mask() To: Thomas Gleixner , , Marc Zyngier , References: <048ff3bb-09d1-2e60-4f3b-611e2bfde7aa@omp.ru> <87cyli5zj7.ffs@tglx> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: Date: Mon, 9 Sep 2024 22:23:21 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <87cyli5zj7.ffs@tglx> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 6.1.1, Database issued on: 09/09/2024 18:56:08 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 187638 [Sep 09 2024] X-KSE-AntiSpam-Info: Version: 6.1.1.5 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 32 0.3.32 766319f57b3d5e49f2c79a76e7d7087b621090df X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.81.96 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.81.96 in (user) dbl.spamhaus.org} X-KSE-AntiSpam-Info: 127.0.0.199:7.1.2;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;omp.ru:7.1.1 X-KSE-AntiSpam-Info: FromAlignment: s X-KSE-AntiSpam-Info: ApMailHostAddress: 31.173.81.96 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 09/09/2024 19:00:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 9/9/2024 4:30:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit On 9/5/24 10:29 AM, Thomas Gleixner wrote: [...] >> ARM GIC arch v2 spec claims support for just 8 CPU interfaces. However, >> looking at the GIC driver's irq_set_affinity() method, it seems that the >> passed CPU mask may contain the logical CPU #s beyond 8, and that method s/8/7/, of course... :-< >> filters them out before reading gic_cpu_map[], bailing out with >> -EINVAL. > > The reasoning is correct in theory, but in reality it's a non problem. Frankly, before finalizing this patch I had tried to ascertain whether cpumask could contain CPUs with the logical #s higher than 8 but that was taking way too much time and I gave up... :-) > Simply because processors which use this GIC version cannot have more > than 8 cores. And big.LITTLE not involved? > That means num_possible_cpus() <= 8 so the cpumask handed in cannot have > bits >= 8 set. Ergo for_each_cpu() can't return a bit which is >= 8. Perhaps adding WARN_ON() would make some sense though? :-) > Thanks > > tglx MBR, Sergey