Patch "mtd: nand: mxc: fix obiwan error in mxc_nand_v[12]_ooblayout_free() functions" has been added to the 4.7-stable tree

This is a note to let you know that I've just added the patch titled

mtd: nand: mxc: fix obiwan error in mxc_nand_v[12]_ooblayout_free() functions

to the 4.7-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:
mtd-nand-mxc-fix-obiwan-error-in-mxc_nand_v_ooblayout_free-functions.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Lothar=20Wa=C3=9Fmann?= <[email protected]>
Date: Mon, 19 Sep 2016 11:09:40 +0200
Subject: mtd: nand: mxc: fix obiwan error in mxc_nand_v[12]_ooblayout_free() functions
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From: Lothar Waßmann <[email protected]>

commit 38178e7b88dcbe1ab384f27a7370074e774dda81 upstream.

commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops") introduced a regression accessing the OOB area from the mxc_nand driver due to an Obiwan error in the mxc_nand_v[12]_ooblayout_free() functions. They report a bogus oobregion { 64, 7 } which leads to errors accessing bogus data when reading the oob area.

Prior to the commit the mtd-oobtest module could be run without any errors. With the offending commit, this test fails with results like:

|Running mtd-oobtest
|
|=================================================
|mtd_oobtest: MTD device: 5
|mtd_oobtest: MTD device size 524288, eraseblock size 131072, page size 2048, count of eraseblocks 4, pages per eraseblock 64, OOB size 64
|mtd_test: scanning for bad eraseblocks
|mtd_test: scanned 4 eraseblocks, 0 are bad
|mtd_oobtest: test 1 of 5
|mtd_oobtest: writing OOBs of whole device
|mtd_oobtest: written up to eraseblock 0
|mtd_oobtest: written 4 eraseblocks
|mtd_oobtest: verifying all eraseblocks
|mtd_oobtest: error @addr[0x0:0x19] 0x9a -> 0x78 diff 0xe2
|mtd_oobtest: error @addr[0x0:0x1a] 0xcc -> 0x0 diff 0xcc
|mtd_oobtest: error @addr[0x0:0x1b] 0xe0 -> 0x85 diff 0x65
|mtd_oobtest: error @addr[0x0:0x1c] 0x60 -> 0x62 diff 0x2
|mtd_oobtest: error @addr[0x0:0x1d] 0x69 -> 0x45 diff 0x2c
|mtd_oobtest: error @addr[0x0:0x1e] 0xcd -> 0xa0 diff 0x6d
|mtd_oobtest: error @addr[0x0:0x1f] 0xf2 -> 0x60 diff 0x92
|mtd_oobtest: error: verify failed at 0x0

[...]

---
 drivers/mtd/nand/mxc_nand.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -943,7 +943,7 @@ static int mxc_v2_ooblayout_free(struct
 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
 	int stepsize = nand_chip->ecc.bytes == 9 ? 16 : 26;
 
-	if (section > nand_chip->ecc.steps)
+	if (section >= nand_chip->ecc.steps)
 		return -ERANGE;
 
 	if (!section) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/mtd-nand-mxc-fix-obiwan-error-in-mxc_nand_v_ooblayout_free-functions.patch