From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jagan Teki Date: Mon, 26 Nov 2018 16:42:48 +0530 Subject: [U-Boot] [PATCH v3 11/11] mtd: sf: Make sf_mtd.c more robust In-Reply-To: <20181126094238.3bf4a76a@bbrezillon> References: <20181119205955.32042-1-boris.brezillon@bootlin.com> <20181119205955.32042-12-boris.brezillon@bootlin.com> <20181122094056.21a75afe@bbrezillon> <20181126094238.3bf4a76a@bbrezillon> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 26/11/18 2:12 PM, Boris Brezillon wrote: > Hi Jagan, > > On Thu, 22 Nov 2018 09:40:56 +0100 > Boris Brezillon wrote: > >>>> + /* >>>> + * Setting mtd->priv to NULL is the best we can do. Thanks to that, >>>> + * the MTD layer can still call mtd hooks without risking a >>>> + * use-after-free bug. Still, things should be fixed to prevent the >>>> + * spi_flash object from being destroyed when del_mtd_device() fails. >>>> + */ >>>> + sf_mtd_info.priv = NULL; >>>> + printf("Failed to unregister MTD %s and the spi_flash object is going away: you're in deep trouble!", >>>> + sf_mtd_info.name); >>> >>> Why do we need this print? >> >> Yes we do, just to keep the user informed that something bad happened >> and its spi-flash is no longer usable (at least through the MTD layer). >> >>> can't we do the same thing in MTD core >>> itself, so-that it can be generic for all flash objects. >> >> del_mtd_device() can fail, so it's the caller responsibility to decide >> what to do when that happens. Some users will propagate the error to >> the upper layer and maybe cancel the device removal (AFAICT, >> driver->remove() can return an error, not sure what happens in this >> case though). For others, like spi-flash, the device will go away, and >> all subsequent accesses will fail. > > I'm about to send a new version fixing the problem I mentioned in patch > 3, but before doing that, I'd like to know if my answer convinced you or > if you'd still prefer this message to go away (or be placed in > mtdcore/mtdpart.c). I'm thinking of having the message still in MTD by showing which interface it would belongs, along with the details.