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[34.127.86.51]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c8242ba1bacsm607897a12.23.2026.05.05.20.45.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2026 20:45:41 -0700 (PDT) Date: Wed, 6 May 2026 03:45:36 +0000 From: Benson Leung To: Andrei Kuchynski Cc: Lee Jones , Benson Leung , Sergey Senozhatsky , Guenter Roeck , Tzung-Bi Shih , Logan Gunthorpe , Greg Kroah-Hartman , chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mfd: cros_ec: Delay dev_set_drvdata() until probe success Message-ID: References: <20260427131721.1165078-1-akuchynski@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="i1JlCb1XYyQceS4y" Content-Disposition: inline In-Reply-To: <20260427131721.1165078-1-akuchynski@chromium.org> --i1JlCb1XYyQceS4y Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Andrei, On Mon, Apr 27, 2026 at 01:17:21PM +0000, Andrei Kuchynski wrote: > If ec_device_probe() fails, cros_ec_class_release releases memory for the > cros_ec_dev structure. However, because the drvdata was already set, > sub-drivers like cros_ec_typec can still retrieve the stale pointer via t= he > platform device. This leads to a use-after-free when cros_ec_typec attemp= ts > to access &typec->ec->ec->dev on a device that has already been released. > Move dev_set_drvdata() to ensure that the pointer is only made available > once all initialization steps have succeeded. >=20 > sysfs: cannot create duplicate filename '/class/chromeos/cros_ec' > Call trace: > sysfs_do_create_link_sd+0x94/0xdc > sysfs_create_link+0x30/0x44 > device_add_class_symlinks+0x90/0x13c > device_add+0xf0/0x50c > ec_device_probe+0x150/0x4f0 > platform_probe+0xa0/0xe0 > ... > BUG: KASAN: invalid-access in __memcpy+0x44/0x230 > Write at addr f5ffff809e2d33ac by task kworker/u32:5/125 > Pointer tag: [f5], memory tag: [fe] > Tainted : [W]=3DWARN, [O]=3DOOT_MODULE > Hardware name: Google Navi unprovisioned 0x7FFFFFFF/sku0 board/sku3 > Workqueue: events_unbound deferred_probe_work_func > Call trace: > __memcpy+0x44/0x230 > cros_ec_check_features+0x60/0xcc [cros_ec_proto] > cros_typec_probe+0xe8/0x6e0 [cros_ec_typec] > platform_probe+0xa0/0xe0 >=20 > Cc: stable@vger.kernel.org > Fixes: 1c1d152cc5ac ("platform/chrome: cros_ec_dev - utilize new cdev_dev= ice_add helper function") > Co-developed-by: Sergey Senozhatsky > Signed-off-by: Sergey Senozhatsky > Signed-off-by: Andrei Kuchynski Reviewed-by: Benson Leung > --- > drivers/mfd/cros_ec_dev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) >=20 > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c > index 39430dd44e30c..56fb7cceafc6c 100644 > --- a/drivers/mfd/cros_ec_dev.c > +++ b/drivers/mfd/cros_ec_dev.c > @@ -195,7 +195,6 @@ static int ec_device_probe(struct platform_device *pd= ev) > if (!ec) > return retval; > =20 > - dev_set_drvdata(dev, ec); > ec->ec_dev =3D dev_get_drvdata(dev->parent); > ec->dev =3D dev; > ec->cmd_offset =3D ec_platform->cmd_offset; > @@ -237,6 +236,8 @@ static int ec_device_probe(struct platform_device *pd= ev) > if (retval) > goto failed; > =20 > + dev_set_drvdata(dev, ec); > + > /* check whether this EC is a sensor hub. */ > if (cros_ec_get_sensor_count(ec) > 0) { > retval =3D mfd_add_hotplug_devices(ec->dev, > --=20 > 2.54.0.rc2.544.gc7ae2d5bb8-goog >=20 --i1JlCb1XYyQceS4y Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQQCtZK6p/AktxXfkOlzbaomhzOwwgUCafq5YAAKCRBzbaomhzOw ws9gAP4o/Y97BIaEjbh6PIhp9H7uWtUiizV3OOo5ubeMh3h+UAEArrSpYxJLsUf7 ascjppNyslvTH/yfwtUT/0Tw00Qe1AI= =+yyJ -----END PGP SIGNATURE----- --i1JlCb1XYyQceS4y--