From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 07 Jun 2023 13:02:21 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1q6qvm-00EF4F-Im for lore@lore.pengutronix.de; Wed, 07 Jun 2023 13:02:21 +0200 Received: from localhost ([127.0.0.1] helo=metis.ext.pengutronix.de) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1q6qvi-0001Jr-KG; Wed, 07 Jun 2023 13:02:18 +0200 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1q6qvg-0001Je-Ra; Wed, 07 Jun 2023 13:02:16 +0200 Message-ID: Date: Wed, 7 Jun 2023 13:02:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Content-Language: en-US To: oss-tools@pengutronix.de References: <20230607080818.715192-1-a.fatoum@pengutronix.de> From: Ahmad Fatoum In-Reply-To: <20230607080818.715192-1-a.fatoum@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [OSS-Tools] [PATCH] libdt: fix of_get_devicepath looking up sibling if device unavailable X-BeenThere: oss-tools@pengutronix.de X-Mailman-Version: 2.1.29 Precedence: list List-Id: Pengutronix Public Open-Source-Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "OSS-Tools" X-SA-Exim-Connect-IP: 127.0.0.1 X-SA-Exim-Mail-From: oss-tools-bounces@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false On 07.06.23 10:08, Ahmad Fatoum wrote: > of_get_devicepath code flow is split into two: > > A) Either the device tree node in question has a direct udev_device > associated with it > > B) Or we assume it's a partition and lookup udev_device for the parent > first, before finding a child udev_device or setting a partition > offset within the parent udev_device. > > Since v2017.03.0, we have had a fallthrough from case A into case B: > If we have a udev_device, but it's neither a EEPROMs, MTDs or block > device, we just consider it a partition. This is problematic, because > this may result in us pointing at a very different device: > > - backend points at a SD-Card host. Host is enabled, but SD-Card > is not inserted, so no block device > > - case A fails, so it's assumed it's a partition and case B > uses parent SoC bus to lookup appropriate device > > - We fall through into the second device_find_block_device, which > will take the first matching block device across the SoC. So > we could end up with the eMMC: a completely different device > than what was pointed at. > > Fixes: 929ed64cb42f ("of_get_devicepath: make partition finding more robust") > Signed-off-by: Ahmad Fatoum Patch applied to next. > --- > src/libdt.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/src/libdt.c b/src/libdt.c > index e54d7fb5649d..7b99efe5b2de 100644 > --- a/src/libdt.c > +++ b/src/libdt.c > @@ -2492,9 +2492,11 @@ int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t > } > > /* > - * If we found a device but couldn't classify it above, we fall > - * through. > + * If we find a udev_device but couldn't classify it above, > + * it's an error. Falling through would mean to handle it as a > + * partition and could lead us to return an arbitrary sibling device > */ > + return -ENODEV; > } > > /* -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |