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[2003:ea:8f26:6400:d1a1:ef77:d584:db28]) by smtp.googlemail.com with ESMTPSA id q124sm5473308wma.5.2019.10.16.12.53.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Oct 2019 12:53:36 -0700 (PDT) From: Heiner Kallweit Subject: [PATCH net-next] net: phy: avoid NPE if read_page/write_page callbacks are not available To: Andrew Lunn , Florian Fainelli , David Miller Cc: "netdev@vger.kernel.org" Message-ID: <41aba46c-6d75-9a15-9360-1336110dd28e@gmail.com> Date: Wed, 16 Oct 2019 21:53:31 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently there's a bug in the module subsystem [0] preventing load of the PHY driver module on certain systems (as one symptom). This results in a NPE on such systems for the following reason: Instead of the correct PHY driver the genphy driver is loaded that doesn't implement the read_page/write_page callbacks. Every call to phy_read_paged() et al will result in a NPE therefore. In parallel to fixing the root cause we should make sure that this one and maybe similar issues in other subsystems don't result in a NPE in phylib. So let's check for the callbacks before using them and warn once if they are not available. [0] https://marc.info/?t=157072642100001&r=1&w=2 Signed-off-by: Heiner Kallweit --- drivers/net/phy/phy-core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c index 9412669b5..0ae1722ba 100644 --- a/drivers/net/phy/phy-core.c +++ b/drivers/net/phy/phy-core.c @@ -689,11 +689,17 @@ EXPORT_SYMBOL_GPL(phy_modify_mmd); static int __phy_read_page(struct phy_device *phydev) { + if (WARN_ONCE(!phydev->drv->read_page, "read_page callback not available, PHY driver not loaded?\n")) + return -EOPNOTSUPP; + return phydev->drv->read_page(phydev); } static int __phy_write_page(struct phy_device *phydev, int page) { + if (WARN_ONCE(!phydev->drv->write_page, "write_page callback not available, PHY driver not loaded?\n")) + return -EOPNOTSUPP; + return phydev->drv->write_page(phydev, page); } -- 2.23.0