From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67CA8179201; Fri, 29 Mar 2024 12:40:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711716051; cv=none; b=fsIBZz3Dtmsw4jaB0IWZA5aUGD2FdnUfwYlajBFJKJd2414kp4sdOkktPk9mM1/N9KLnqmOIjv2LkgPqlD0MURF9CoJQJObMzNNjtnEV3xqP0yYgGynAd2ekm5y4w/zfQ08V1W9rCzWsA1ybSfyyg2xmrIRBtWQAFR4WUSv8nr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711716051; c=relaxed/simple; bh=uRO9hNSHchqspmCb1F6je6akXTN4Hy8qBEMg95DG9jg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MxpwZyMmtovYw7hVynB4z2n62Egex+M6Z/63D2tUSlcL3dPERQ8+ByUGS7MvUpdShV9J7rmkZQB5HCbzZ4dqPJ37WjP1jXaMJ7M5j+4MViWrO4pSU2088kIsUmehiM3Zsevpn2gedPTZLW3sS73qsdOThKmHmV1aaIzl1/E8Tec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NrZKtPVt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NrZKtPVt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95DACC43390; Fri, 29 Mar 2024 12:40:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711716051; bh=uRO9hNSHchqspmCb1F6je6akXTN4Hy8qBEMg95DG9jg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NrZKtPVtBxsI1CXM7WGuCkhix7O9SUgBdXFPSSxc0cTFh1+nJm+2RvxxChlUc0ct1 q2UvZyv2UNtrYBMz2ybacAxfrR3meAKJUl4+EaxJEQLbzIgbCw555SMumiHpwRC/Sb sTyysz5wmC0YDXiD6bEpftRrY4wEYF0ImWn74cKzxX5nmF3A9EpdSmdwKFdDzCovjD R5xc2ZtDLUHKvKgopKgX8d14QNHOzdF93mj+35Yfae8pSNahMsS51VQ70Cp4BK+u3e phahzODtPeGYVfv47i1tquE1CRDUAyV8R+RcOUZYeGXraW0qtE4g3A3ItuADBcWVat vjS0wA0QkFF7w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: C Cheng , Bo Ye , AngeloGioacchino Del Regno , "Rafael J . Wysocki" , Sasha Levin , rafael@kernel.org, daniel.lezcano@linaro.org, matthias.bgg@gmail.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: [PATCH AUTOSEL 6.8 28/98] cpuidle: Avoid potential overflow in integer multiplication Date: Fri, 29 Mar 2024 08:36:59 -0400 Message-ID: <20240329123919.3087149-28-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329123919.3087149-1-sashal@kernel.org> References: <20240329123919.3087149-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.8.2 Content-Transfer-Encoding: 8bit From: C Cheng [ Upstream commit 88390dd788db485912ee7f9a8d3d56fc5265d52f ] In detail: In C language, when you perform a multiplication operation, if both operands are of int type, the multiplication operation is performed on the int type, and then the result is converted to the target type. This means that if the product of int type multiplication exceeds the range that int type can represent, an overflow will occur even if you store the result in a variable of int64_t type. For a multiplication of two int values, it is better to use mul_u32_u32() rather than s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC to avoid potential overflow happenning. Signed-off-by: C Cheng Signed-off-by: Bo Ye Reviewed-by: AngeloGioacchino Del Regno [ rjw: New subject ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/cpuidle/driver.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index d9cda7f6ccb98..cf5873cc45dc8 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "cpuidle.h" @@ -187,7 +188,7 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv) s->target_residency = div_u64(s->target_residency_ns, NSEC_PER_USEC); if (s->exit_latency > 0) - s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC; + s->exit_latency_ns = mul_u32_u32(s->exit_latency, NSEC_PER_USEC); else if (s->exit_latency_ns < 0) s->exit_latency_ns = 0; else -- 2.43.0 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 C45CEC6FD1F for ; Fri, 29 Mar 2024 12:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=T6AkJWzPSdYnBgQ37LcxnW53LRpzi2FnwepwUHS6R0o=; b=U1XWnxCUqPYTjR Bz6Tpc6m0dVAzu61Uy+TV/XJDOVhgt75Xmr5DBAX39F3nr1ecpj5kuaDTM7eP4WEUC3w8bCQDUMF7 LFBhSg6N6a4OgBt9bgpFCZFKGGn/WqjKXYPQ8+8xgsoszpguGlM+EBwF9oDg6swoLmFi32jUw2sBz uE0/okXyiss2CiYYTzKaBNSggOa9An7/PxaOLbwE9rJ1082QYyaNo/GJZokgHywIHDJWTpxvdA0dM 9eb8HmpV/H41QMNTiHSi8fSr+f7ta4wBgbPzHCdTHlU+wyJrTxlykqMOElLyJuKmJU8CD+r6JfQza hy3jjjakvD3XXAaWmTzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqBae-00000000RBq-2cgb; Fri, 29 Mar 2024 12:44:13 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqBXT-00000000QR6-3ToP; Fri, 29 Mar 2024 12:40:57 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=7eQKwf0Z+/IU8P6FzXPXgNYGM69mSrUpyYay8JCX58M=; b=ibHEFBX3oQRpp+n15aHrdAznQQ Od6K9QOrn0sevOwyehP1rUxMeNSobOqShjGkfrvdqDro+yBkLzQMUVAUzpHvXxf7Wb3EeIFJiVFwX Fyi18dIFn0e7u6iK7BAxHYn8afRc6KMVNfrVnO/qPPdefcRJKF7PZfWLrLA59mMerHmN4fSZnDlYy TTphV41O/AD1LZKhTxazbuwS/AuRx5vOL7PRCy8m74EC1/xBxHcJSvy+0M+VIV069ZGKQyQO4t5A+ 3QRq5Y//PlWK0MDFwqYC+1WlVDf+NG6RqS5z1mqdJ+2KGBHVtqIVwEtuhaS5l4mrO4F6l6hD1Vhm/ j0XMXV7Q==; Received: from dfw.source.kernel.org ([139.178.84.217]) by desiato.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqBXQ-00000001Yqp-3R1g; Fri, 29 Mar 2024 12:40:54 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 2ED5061920; Fri, 29 Mar 2024 12:40:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95DACC43390; Fri, 29 Mar 2024 12:40:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711716051; bh=uRO9hNSHchqspmCb1F6je6akXTN4Hy8qBEMg95DG9jg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NrZKtPVtBxsI1CXM7WGuCkhix7O9SUgBdXFPSSxc0cTFh1+nJm+2RvxxChlUc0ct1 q2UvZyv2UNtrYBMz2ybacAxfrR3meAKJUl4+EaxJEQLbzIgbCw555SMumiHpwRC/Sb sTyysz5wmC0YDXiD6bEpftRrY4wEYF0ImWn74cKzxX5nmF3A9EpdSmdwKFdDzCovjD R5xc2ZtDLUHKvKgopKgX8d14QNHOzdF93mj+35Yfae8pSNahMsS51VQ70Cp4BK+u3e phahzODtPeGYVfv47i1tquE1CRDUAyV8R+RcOUZYeGXraW0qtE4g3A3ItuADBcWVat vjS0wA0QkFF7w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: C Cheng , Bo Ye , AngeloGioacchino Del Regno , "Rafael J . Wysocki" , Sasha Levin , rafael@kernel.org, daniel.lezcano@linaro.org, matthias.bgg@gmail.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: [PATCH AUTOSEL 6.8 28/98] cpuidle: Avoid potential overflow in integer multiplication Date: Fri, 29 Mar 2024 08:36:59 -0400 Message-ID: <20240329123919.3087149-28-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329123919.3087149-1-sashal@kernel.org> References: <20240329123919.3087149-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.8.2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240329_124053_100985_74668FEA X-CRM114-Status: GOOD ( 13.33 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: C Cheng [ Upstream commit 88390dd788db485912ee7f9a8d3d56fc5265d52f ] In detail: In C language, when you perform a multiplication operation, if both operands are of int type, the multiplication operation is performed on the int type, and then the result is converted to the target type. This means that if the product of int type multiplication exceeds the range that int type can represent, an overflow will occur even if you store the result in a variable of int64_t type. For a multiplication of two int values, it is better to use mul_u32_u32() rather than s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC to avoid potential overflow happenning. Signed-off-by: C Cheng Signed-off-by: Bo Ye Reviewed-by: AngeloGioacchino Del Regno [ rjw: New subject ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/cpuidle/driver.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index d9cda7f6ccb98..cf5873cc45dc8 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "cpuidle.h" @@ -187,7 +188,7 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv) s->target_residency = div_u64(s->target_residency_ns, NSEC_PER_USEC); if (s->exit_latency > 0) - s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC; + s->exit_latency_ns = mul_u32_u32(s->exit_latency, NSEC_PER_USEC); else if (s->exit_latency_ns < 0) s->exit_latency_ns = 0; else -- 2.43.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel