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Date: Fri, 15 Mar 2024 18:38:38 +0000
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Nikita Kiryushin <kiryushin@ancud.ru>
Cc: Andrew Lunn <andrew@lunn.ch>, Heiner Kallweit <hkallweit1@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Oleksij Rempel <o.rempel@pengutronix.de>, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org
Subject: Re: [PATCH net] net: phy: fix phy_read_poll_timeout argument type in
 genphy_loopback
Message-ID: <ZfSVrge/REaXPF+0@shell.armlinux.org.uk>
References: <20240314164826.161bd398@kernel.org>
 <20240315175052.8049-1-kiryushin@ancud.ru>
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Sender: Russell King (Oracle) <linux@armlinux.org.uk>

On Fri, Mar 15, 2024 at 08:50:52PM +0300, Nikita Kiryushin wrote:
> read_poll_timeout inside phy_read_poll_timeout can set val negative
> in some cases (for example, __mdiobus_read inside phy_read can return
> -EOPNOTSUPP).
> 
> Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
> should fix problems with wrong-signed vals, but I do not see how
> as val is sent to phy_read as is and __val = phy_read (not val)
> is checked for sign.
> 
> Change val type for signed to allow better error handling as done in other
> phy_read_poll_timeout callers. This will not fix any error handling
> by itself, but allows, for example, to modify cond with appropriate
> sign check or check resulting val separately.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
> Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

-- 
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