From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Colin Ian King <colin.king@canonical.com>,
"David S. Miller" <davem@davemloft.net>,
Giuseppe Cavallaro <peppe.cavallaro@st.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: net: stmmac: Add basic EST support for GMAC5+
Date: Thu, 26 Dec 2019 17:14:20 +0000 [thread overview]
Message-ID: <BN8PR12MB326646266EF7CEA29685CF0AD32B0@BN8PR12MB3266.namprd12.prod.outlook.com> (raw)
In-Reply-To: <c1b6b4cc-bc94-8ed6-0098-de9e5321722a@canonical.com>
From: Colin Ian King <colin.king@canonical.com>
Date: Dec/20/2019, 23:49:02 (UTC+00:00)
> Hi,
>
> Static analysis with Coverity has detected a potential issue with the
> following commit:
>
> commit 504723af0d85434be5fb6f2dde0b62644a7f1ead
> Author: Jose Abreu <joabreu@synopsys.com>
> Date: Wed Dec 18 11:33:05 2019 +0100
>
> net: stmmac: Add basic EST support for GMAC5+
>
>
> In function dwmac5_est_configure() we have a u64 total_ctr being
> assigned as follows:
>
> total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000;
>
> The cfg->ctr[1] is a u32, the multiplication of cfg->ctr[1] is a u32
> multiplication operation, so multiplying by 1000000000 can potentially
> cause an overflow. Either cfg->ctr[1] needs to be cast to a u64 or
> 1000000000 should be at least a 1000000000UL to avoid this overflow. I
> was going to fix this but on further inspection I was not sure if the
> original code was intended as:
>
> total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000UL;
> or:
> total_ctr = (cfg->ctr[0] + cfg->ctr[1]) * 1000000000UL;
>
> ..hence I'm flagging this up as potential error.
Thanks for the report. The first option is the correct one as ctr[1] is
seconds and ctr[0] is nanoseconds. Can you send a fix-up patch ?
---
Thanks,
Jose Miguel Abreu
prev parent reply other threads:[~2019-12-26 17:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 23:49 net: stmmac: Add basic EST support for GMAC5+ Colin Ian King
2019-12-26 17:14 ` Jose Abreu [this message]
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