Re: [PATCH v2 3/9] mtd: rawnand: onfi: Fix redundancy detection check

From: Boris Brezillon <boris.brezillon@collabora.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: linux-mtd@lists.infradead.org,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Tudor Ambarus <Tudor.Ambarus@microchip.com>
Subject: Re: [PATCH v2 3/9] mtd: rawnand: onfi: Fix redundancy detection check
Date: Tue, 28 Apr 2020 11:10:54 +0200	[thread overview]
Message-ID: <20200428111054.4a8cfd26@collabora.com> (raw)
In-Reply-To: <20200428105444.0778d750@xps13>

On Tue, 28 Apr 2020 10:54:44 +0200
Miquel Raynal <miquel.raynal@bootlin.com> wrote:

> Hi Boris,
> 
> Boris Brezillon <boris.brezillon@collabora.com> wrote on Sat, 25 Apr
> 2020 10:22:25 +0200:
> 
> > On Fri, 24 Apr 2020 18:40:36 +0200
> > Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >   
> > > During ONFI detection, the CRC derived from the parameter page and the
> > > CRC supposed to be at the end of the parameter page are compared. If
> > > they do not match, the second then the third copies of the page are
> > > tried.
> > > 
> > > The current implementation compares the newly derived CRC with the CRC
> > > contained in the first page only. So if this particular CRC area has
> > > been corrupted, then the detection will fail for a wrong reason.
> > > 
> > > Fix this issue by checking the derived CRC against the right one.
> > >     
> >   
> 
> Yes, but given the fact that we moved this code out of nand_base.c
> sending it to stable would not apply, I don't know what's best in this
> case?

It would at least be backported to a few releases, and you can always
provide a replacement when Greg sends you the 'patch did not apply'
notice. So yes, I think it's worth adding a cc-stable tag here.

> 
> The faulty commit being
> 39138c1f4a31 mtd: rawnand: use bit-wise majority to recover the ONFI param page
> 
> > This one probably deserves Fixes and Cc-stable tags.
> >   
> > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
> > > ---
> > >  drivers/mtd/nand/raw/nand_onfi.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/mtd/nand/raw/nand_onfi.c b/drivers/mtd/nand/raw/nand_onfi.c
> > > index 0b879bd0a68c..8fe8d7bdd203 100644
> > > --- a/drivers/mtd/nand/raw/nand_onfi.c
> > > +++ b/drivers/mtd/nand/raw/nand_onfi.c
> > > @@ -173,7 +173,7 @@ int nand_onfi_detect(struct nand_chip *chip)
> > >  		}
> > >  
> > >  		if (onfi_crc16(ONFI_CRC_BASE, (u8 *)&p[i], 254) ==
> > > -				le16_to_cpu(p->crc)) {
> > > +		    le16_to_cpu(p[i].crc)) {
> > >  			if (i)
> > >  				memcpy(p, &p[i], sizeof(*p));
> > >  			break;    
> >   
> 
> Thanks,
> Miquèl

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/