From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AFC561C8613 for ; Fri, 14 Feb 2025 21:06:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739567218; cv=none; b=XAUP02QtHOVZ2Avnmhrjyieqswf4gqYsrLMjeQBRu7CBF+lEHB1qSVxQlvqMTm14AB6WVnngFKGaEJILpwmNCkIJFApyWW03ETMzi+HbwTM8aFfMIPuApmsp4XzNQCc12xK+ACkjKhd4ZDlSZT6WJIqObEwbgNa2KXaBsqUdFR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739567218; c=relaxed/simple; bh=eBLGG68Or9yjsiP4CLRRkY0iPolcI0GPak3U8DpQKvs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=XRNiDJyKhEhgO8UpvxyIp0z+iWoNzMjiGtqd88+8uk3pmtVsP+epMzqIL2pX+XZaEJRrFPnXMsXVmFNzGRHsh71G33Xj1+xqJ8Y2Dm1+wom6QYuac7x3euq0+70Q6M3/kdtWGg6HfSMI0LYMHEGBrkGE/fOHOmb7FggRoJqwVMk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ENF1ol3o; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ENF1ol3o" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2210121ac27so9285085ad.1 for ; Fri, 14 Feb 2025 13:06:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1739567216; x=1740172016; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=492QiewuxoOpSiREuMz57X44BumOAwjBNWQNhBoGViE=; b=ENF1ol3oribNwBxJB4/X330Pe8byV4ulcijx0Zyvti6xddv6OdVDJpPmwUuew79ITz 91DZJldWNvVBBCG+sMpWD8qc9DZJrgUmDEwWuwB1rYbmxsTRIJUTp+0IR1jhuql5RqrT 74h55dxmheQmGZy02eqQcgCB0759xYYanJC7bPBa226SNVVmog4fNX9TE03gWf5yARDK XeV4FHcJ5nuhUut2z5x1lghMxmxGMnbpHueOBpzks1PUB9Gl0uTZai0rwJxnbtbH6OmX 9TH3wCOfyv7Xz75PQ5TuLGNW3qsX4Xp8Z0bJDY8yxUP1/ysUeHIp+MiFHJ9oTR3qx4lY PUfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739567216; x=1740172016; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=492QiewuxoOpSiREuMz57X44BumOAwjBNWQNhBoGViE=; b=wc68dBrxE7mqbQXH+NEsVoFBHrBvgl3+lKbRfz9I/84ybQyCn7kfzTDJSjafWtKc8I R/eXnvg5Q5QcMxii+GWRP4tUgbHtnGtucfnDXDRltTmerxRgzkJK/MA2hv0HwVwYQt3o g795tswqx/tSPU1mEA4L5dOaSZ0IjXKyrWNV6v/eBFlrVtyPMe6VmsTE618DVfEZJ23s Pu6ILmdTE77MVXW3CPOATu4p/famge3T4eF9Xt9SBb3OB/eknVI3VYrh6bmPIUBEY1K0 fKh18jtSQ4lhMX8Kv5sC915LSJk51peUUQZ0UfSKY1B0eJBleKqYWGTc/W8+5eIJlxoI SP9Q== X-Forwarded-Encrypted: i=1; AJvYcCUoTCxBj9kSS+R5umygTL2Wqq/WMcRO2LkkkRNoFHfExzTfJrqmg6BqBYwz8QftFsi2qeUj1was3vfZbKE=@vger.kernel.org X-Gm-Message-State: AOJu0YwFeIUErJUN2yF2aEZHl4kvZ8E5wH0wXSLghKzovKcL5c1YMTKl ae3LAHmiOfKexowX9IcvbkomBOjg9Mdm9hsBNT/au3V3ZFQcNXW1wnrHVcujLFAqfRHQ9XuL1xE AtA== X-Google-Smtp-Source: AGHT+IHTxKpz9YQBehDW94ffNCBW6dSQ66S1eZW769DC4cxPKMriG0SAxEjF//npoSq9l3P1wuWzfkFJfBM= X-Received: from pjbnb2.prod.google.com ([2002:a17:90b:35c2:b0:2fc:c98:ea47]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2b07:b0:21c:1140:136c with SMTP id d9443c01a7336-22103ef2e81mr12121105ad.3.1739567216039; Fri, 14 Feb 2025 13:06:56 -0800 (PST) Date: Fri, 14 Feb 2025 13:06:54 -0800 In-Reply-To: <20240914101728.33148-6-dapeng1.mi@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240914101728.33148-1-dapeng1.mi@linux.intel.com> <20240914101728.33148-6-dapeng1.mi@linux.intel.com> Message-ID: Subject: Re: [kvm-unit-tests patch v6 05/18] x86: pmu: Enlarge cnt[] length to 48 in check_counters_many() From: Sean Christopherson To: Dapeng Mi Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Mingwei Zhang , Xiong Zhang , Zhenyu Wang , Like Xu , Jinrong Liang , Yongwei Ma , Dapeng Mi Content-Type: text/plain; charset="us-ascii" On Sat, Sep 14, 2024, Dapeng Mi wrote: > Considering there are already 8 GP counters and 4 fixed counters on > latest Intel processors, like Sapphire Rapids. The original cnt[] array > length 10 is definitely not enough to cover all supported PMU counters on > these new processors even through currently KVM only supports 3 fixed > counters at most. This would cause out of bound memory access and may trigger > false alarm on PMU counter validation > > It's probably more and more GP and fixed counters are introduced in the > future and then directly extends the cnt[] array length to 48 once and > for all. Base on the layout of IA32_PERF_GLOBAL_CTRL and > IA32_PERF_GLOBAL_STATUS, 48 looks enough in near feature. > > Reviewed-by: Jim Mattson > Signed-off-by: Dapeng Mi > --- > x86/pmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/x86/pmu.c b/x86/pmu.c > index a0268db8..b4de2680 100644 > --- a/x86/pmu.c > +++ b/x86/pmu.c > @@ -255,7 +255,7 @@ static void check_fixed_counters(void) > > static void check_counters_many(void) > { > - pmu_counter_t cnt[10]; > + pmu_counter_t cnt[48]; ARGH. Since the *entire* purpose of increasing the size is to guard against buffer overflow, add an assert that the loop doesn't overflow. > int i, n; > > for (i = 0, n = 0; n < pmu.nr_gp_counters; i++) { > -- > 2.40.1 >