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 E2EC918AF8; Fri, 29 Mar 2024 12:30:19 +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=1711715420; cv=none; b=Ju6kFhbB/Ws204lGYnCyFu9S8wN6ML1bcpLUzFA+h0XciLCjB4xIcNnMYCoA8fTGJunsqHXhr5edcarSfwL6lOpZQchKTioMaPoZdsu2TV2ctocZmvAx8VlOn1o2wrx2SgLI5fyMV4lv3UuFw5gyYKvlh34hQ5tPGeNesw71fHU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711715420; c=relaxed/simple; bh=uRO9hNSHchqspmCb1F6je6akXTN4Hy8qBEMg95DG9jg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=n41lsxeUwuYMbP+PZ8MBUAYaR4vKKDNYS+iziYwX6d/5qRKUBh1ZPxJno+RaWyKufLAp8D369GhxQiEjmXaJZv80C8iL7pVp+ueCVaZY/2IHN3eTtWi1Rt2ktHKOHz94gvvHwa4GDvmVqXBtr40hIU32P+8iv5Xo7dY1KCocFUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SFlaGjzj; 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="SFlaGjzj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FCF1C433F1; Fri, 29 Mar 2024 12:30:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711715419; bh=uRO9hNSHchqspmCb1F6je6akXTN4Hy8qBEMg95DG9jg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SFlaGjzjCEXWlMQSkYxntF1dfRWgtVpKNt8cyNEAG61rCUcy6A6IVWT4DTzAEQndR zg3BhendHhFcs7Sfoqze9oaafHh8ZE+nJ46WEvq82xCuYCl2qda7MWcJz+yaG3mdPz DKYbfj9VhFPXX7hSav1mpiShXUnUUu8gln2Z+VRYTa6sRGODOaXc0Njv/QsTewbZT+ 1v+2DJE26Jv9H3sy502RIK2iUeEBLgdEezZspfPHOWkBo3BhEaMNb6i7Rcz8MkBKYV WMMg0Ie+H0o0aCcvsU89iRrMNVw+X+KYaD6L9mzAD4DaQYoGR4yp+lJ57SlkIpjBRP jUkHr3hklRWqQ== 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 6.6 14/52] cpuidle: Avoid potential overflow in integer multiplication Date: Fri, 29 Mar 2024 08:28:44 -0400 Message-ID: <20240329122956.3083859-14-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329122956.3083859-1-sashal@kernel.org> References: <20240329122956.3083859-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.23 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