This is a note to let you know that I've just added the patch titled nand: fix wrong default oob layout for small pages using soft ecc to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nand-fix-wrong-default-oob-layout-for-small-pages-using-soft-ecc.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f7f8c1756e9a5f1258a7cc6b663f8451b724900f Mon Sep 17 00:00:00 2001 From: Miquel Raynal <miquel.raynal@xxxxxxxxxxxxxxxxxx> Date: Wed, 5 Jul 2017 08:51:09 +0200 Subject: nand: fix wrong default oob layout for small pages using soft ecc From: Miquel Raynal <miquel.raynal@xxxxxxxxxxxxxxxxxx> commit f7f8c1756e9a5f1258a7cc6b663f8451b724900f upstream. When using soft ecc, if no ooblayout is given, the core automatically uses one of the nand_ooblayout_{sp,lp}*() functions to determine the layout inside the out of band data. Until kernel version 4.6, struct nand_ecclayout was used for that purpose. During the migration from 4.6 to 4.7, an error shown up in the small page layout, in the case oob section is only 8 bytes long. The layout was using three bytes (0, 1, 2) for ecc, two bytes (3, 4) as free bytes, one byte (5) for bad block marker and finally two bytes (6, 7) as free bytes, as shown there: [linux-4.6] drivers/mtd/nand/nand_base.c:52 static struct nand_ecclayout nand_oob_8 = { .eccbytes = 3, .eccpos = {0, 1, 2}, .oobfree = { {.offset = 3, .length = 2}, {.offset = 6, .length = 2} } }; This fixes the current implementation which is incoherent. It references bit 3 at the same time as an ecc byte and a free byte. Furthermore, it is clear with the previous implementation that there is only one ecc section with 8 bytes oob sections. We shall return -ERANGE in the nand_ooblayout_ecc_sp() function when asked for the second section. Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxxxxxxxxx> Fixes: 41b207a70d3a ("mtd: nand: implement the default mtd_ooblayout_ops") Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/mtd/nand/nand_base.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -64,8 +64,14 @@ static int nand_ooblayout_ecc_sp(struct if (!section) { oobregion->offset = 0; - oobregion->length = 4; + if (mtd->oobsize == 16) + oobregion->length = 4; + else + oobregion->length = 3; } else { + if (mtd->oobsize == 8) + return -ERANGE; + oobregion->offset = 6; oobregion->length = ecc->total - 4; } Patches currently in stable-queue which might be from miquel.raynal@xxxxxxxxxxxxxxxxxx are queue-4.9/nand-fix-wrong-default-oob-layout-for-small-pages-using-soft-ecc.patch