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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 500EFC41535 for ; Wed, 20 Dec 2023 01:47:00 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rFlf2-0001cE-T4; Tue, 19 Dec 2023 20:46:12 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rFlf0-0001bY-Ip for qemu-devel@nongnu.org; Tue, 19 Dec 2023 20:46:10 -0500 Received: from mail-qv1-xf2b.google.com ([2607:f8b0:4864:20::f2b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rFley-0005zd-BX for qemu-devel@nongnu.org; Tue, 19 Dec 2023 20:46:10 -0500 Received: by mail-qv1-xf2b.google.com with SMTP id 6a1803df08f44-67ab5e015aaso38569086d6.0 for ; Tue, 19 Dec 2023 17:46:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1703036766; x=1703641566; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=kqn3KMJ5g/VK+CZXLjmrErjc7rLMnYIMFlq297CCPAM=; b=hD4Y/+Wi38SgJrX/MQlyBMdRwKv25UdWqWnRZaULB6mOHM0Z5H0Z+awn7jAB0iH6bJ 0ISR1l6AQOX1ZjxEO6nNbldiNA1KhZlXxrXrF/bvQloSF0KD0PPNDd1cLMAKa45plE+L WFsYHXEFQ+npLzAhV3SvFIRJJiMqlmUfgND6C1mUyIfpg4g9Sh+6gTrk+AYrFQAU9Rgd IlChozXuaupgte9/0Wt54zaWY1TIM2ul9E4ca9BhAlFsDbOKwpXgkPsOWrWZy0UCzzrC xS312iyZ9WvSnrEIFlxkqgsIlL3nKUgPlSXSIkDVKYpuIm2FfedNZOrQQ1OBI/8pBvO1 3oGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1703036767; x=1703641567; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=kqn3KMJ5g/VK+CZXLjmrErjc7rLMnYIMFlq297CCPAM=; b=AR41npLTemaQzBJ8+6xb2gyxiOxLZqlGhTgZdPMCpa9I/NoB2QAElhTfmIzM47qb+r ja3jUl9Ek+/znr7TQ8TG9yz6W4L++VhL2MzNuim/V/TQQzru0L9R/aWiu+hW1yZbUTS4 NYBbAeBFwXs5WvI0UqLvhGo76ZzNYkdT7q7DcmVVswUhFnxVGrwf44V9YhZ3lOTO5GD8 M6pnDSRZzIHfhfhv7SKzr9WCgmWgRiJEnF/hWTHWOwdTe7A3aZER1pIkG6H49jQ63Mau e/upxzRFyx9UL6ThJ91Sxf5ZGKMQFp1lcDlIR9NOqOKYj3touLjxFv6QrGqFxapXvdzV cmWw== X-Gm-Message-State: AOJu0YztWdQ0Met6iy8xCyhJlD+QT2Moe4Eh3f3K0iOImDg//wC9HHps 2Sa/gX7voGA5Yotd0CtVej7V6w== X-Google-Smtp-Source: AGHT+IHlgBpPcwiizwD2l5zncernGUmljdLJcxnwmopKyCq41nlbCQnUyzFY+Dthlix4Qs3JMg95DA== X-Received: by 2002:a05:6214:2686:b0:67f:38c0:e97c with SMTP id gm6-20020a056214268600b0067f38c0e97cmr7515004qvb.72.1703036766684; Tue, 19 Dec 2023 17:46:06 -0800 (PST) Received: from [192.168.44.231] ([172.58.160.19]) by smtp.gmail.com with ESMTPSA id jx13-20020a0562142b0d00b0067f4f07587csm1725740qvb.69.2023.12.19.17.46.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 Dec 2023 17:46:05 -0800 (PST) Message-ID: <1c5f886a-821e-46ff-bcea-045b07ebf809@linaro.org> Date: Tue, 19 Dec 2023 17:45:53 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ppc/spapr: Fix ubsan warning with unaligned pointer access To: Daniel Hoffman , qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org, Alexey Kardashevskiy , David Gibson , "open list:Virtual Open Firm..." References: <20231217001441.146344-1-dhoff749@gmail.com> Content-Language: en-US From: Richard Henderson In-Reply-To: <20231217001441.146344-1-dhoff749@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::f2b; envelope-from=richard.henderson@linaro.org; helo=mail-qv1-xf2b.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 12/16/23 16:14, Daniel Hoffman wrote: > Found while running QTest with UBsan. Unaligned pointers appear to be > valid, so moving the read to an explicit memcpy to an intermediate. > --- > hw/ppc/vof.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c > index e3b430a81f4..609a51c645d 100644 > --- a/hw/ppc/vof.c > +++ b/hw/ppc/vof.c > @@ -646,7 +646,10 @@ static void vof_dt_memory_available(void *fdt, GArray *claimed, uint64_t base) > mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen); > g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc)); > if (sc == 2) { > - mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + sizeof(uint32_t) * ac)); > + /* Pointer may be unaligned */ > + uint64_t mem0_end_copy; > + memcpy(&mem0_end_copy, mem0_reg + sizeof(uint32_t) * ac, sizeof(mem0_end_copy)); > + mem0_end = be64_to_cpu(mem0_end_copy); mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac); r~